gowebbuild/vendor/github.com/evanw/esbuild/internal/bundler/linker.go

5582 lines
199 KiB
Go
Raw Normal View History

package bundler
import (
"bytes"
"encoding/base64"
"encoding/binary"
"fmt"
"hash"
"path"
"sort"
"strings"
"sync"
"github.com/evanw/esbuild/internal/ast"
"github.com/evanw/esbuild/internal/compat"
"github.com/evanw/esbuild/internal/config"
"github.com/evanw/esbuild/internal/css_ast"
"github.com/evanw/esbuild/internal/css_printer"
"github.com/evanw/esbuild/internal/fs"
"github.com/evanw/esbuild/internal/graph"
"github.com/evanw/esbuild/internal/helpers"
"github.com/evanw/esbuild/internal/js_ast"
"github.com/evanw/esbuild/internal/js_lexer"
"github.com/evanw/esbuild/internal/js_printer"
"github.com/evanw/esbuild/internal/logger"
"github.com/evanw/esbuild/internal/renamer"
"github.com/evanw/esbuild/internal/resolver"
"github.com/evanw/esbuild/internal/runtime"
"github.com/evanw/esbuild/internal/sourcemap"
"github.com/evanw/esbuild/internal/xxhash"
)
type linkerContext struct {
options *config.Options
timer *helpers.Timer
log logger.Log
fs fs.FS
res resolver.Resolver
graph graph.LinkerGraph
// This helps avoid an infinite loop when matching imports to exports
cycleDetector []importTracker
// We may need to refer to the CommonJS "module" symbol for exports
unboundModuleRef js_ast.Ref
// We may need to refer to the "__esm" and/or "__commonJS" runtime symbols
cjsRuntimeRef js_ast.Ref
esmRuntimeRef js_ast.Ref
// This represents the parallel computation of source map related data.
// Calling this will block until the computation is done. The resulting value
// is shared between threads and must be treated as immutable.
dataForSourceMaps func() []dataForSourceMap
// This is passed to us from the bundling phase
uniqueKeyPrefix string
uniqueKeyPrefixBytes []byte // This is just "uniqueKeyPrefix" in byte form
}
type partRange struct {
sourceIndex uint32
partIndexBegin uint32
partIndexEnd uint32
}
type chunkInfo struct {
// This is a random string and is used to represent the output path of this
// chunk before the final output path has been computed.
uniqueKey string
filesWithPartsInChunk map[uint32]bool
entryBits helpers.BitSet
// This information is only useful if "isEntryPoint" is true
isEntryPoint bool
sourceIndex uint32 // An index into "c.sources"
entryPointBit uint // An index into "c.graph.EntryPoints"
// For code splitting
crossChunkImports []chunkImport
// This is the representation-specific information
chunkRepr chunkRepr
// This is the final path of this chunk relative to the output directory, but
// without the substitution of the final hash (since it hasn't been computed).
finalTemplate []config.PathTemplate
// This is the final path of this chunk relative to the output directory. It
// is the substitution of the final hash into "finalTemplate".
finalRelPath string
// If non-empty, this chunk needs to generate an external legal comments file.
externalLegalComments []byte
// When this chunk is initially generated in isolation, the output pieces
// will contain slices of the output with the unique keys of other chunks
// omitted.
intermediateOutput intermediateOutput
// This contains the hash for just this chunk without including information
// from the hashes of other chunks. Later on in the linking process, the
// final hash for this chunk will be constructed by merging the isolated
// hashes of all transitive dependencies of this chunk. This is separated
// into two phases like this to handle cycles in the chunk import graph.
waitForIsolatedHash func() []byte
// Other fields relating to the output file for this chunk
jsonMetadataChunkCallback func(finalOutputSize int) helpers.Joiner
outputSourceMap sourcemap.SourceMapPieces
isExecutable bool
}
type chunkImport struct {
chunkIndex uint32
importKind ast.ImportKind
}
type outputPieceIndexKind uint8
const (
outputPieceNone outputPieceIndexKind = iota
outputPieceAssetIndex
outputPieceChunkIndex
)
// This is a chunk of source code followed by a reference to another chunk. For
// example, the file "@import 'CHUNK0001'; body { color: black; }" would be
// represented by two pieces, one with the data "@import '" and another with the
// data "'; body { color: black; }". The first would have the chunk index 1 and
// the second would have an invalid chunk index.
type outputPiece struct {
data []byte
// Note: The "kind" may be "outputPieceNone" in which case there is one piece
// with data and no chunk index. For example, the chunk may not contain any
// imports.
index uint32
kind outputPieceIndexKind
}
type intermediateOutput struct {
// If the chunk doesn't have any references to other chunks, then "pieces" is
// nil and "joiner" contains the contents of the chunk. This is more efficient
// because it avoids doing a join operation twice.
joiner helpers.Joiner
// Otherwise, "pieces" contains the contents of the chunk and "joiner" should
// not be used. Another joiner will have to be constructed later when merging
// the pieces together.
pieces []outputPiece
}
type chunkRepr interface{ isChunk() }
func (*chunkReprJS) isChunk() {}
func (*chunkReprCSS) isChunk() {}
type chunkReprJS struct {
filesInChunkInOrder []uint32
partsInChunkInOrder []partRange
// For code splitting
crossChunkPrefixStmts []js_ast.Stmt
crossChunkSuffixStmts []js_ast.Stmt
exportsToOtherChunks map[js_ast.Ref]string
importsFromOtherChunks map[uint32]crossChunkImportItemArray
}
type chunkReprCSS struct {
externalImportsInOrder []externalImportCSS
filesInChunkInOrder []uint32
}
type externalImportCSS struct {
path logger.Path
conditions []css_ast.Token
conditionImportRecords []ast.ImportRecord
}
// Returns a log where "log.HasErrors()" only returns true if any errors have
// been logged since this call. This is useful when there have already been
// errors logged by other linkers that share the same log.
func wrappedLog(log logger.Log) logger.Log {
var mutex sync.Mutex
var hasErrors bool
addMsg := log.AddMsg
log.AddMsg = func(msg logger.Msg) {
if msg.Kind == logger.Error {
mutex.Lock()
defer mutex.Unlock()
hasErrors = true
}
addMsg(msg)
}
log.HasErrors = func() bool {
mutex.Lock()
defer mutex.Unlock()
return hasErrors
}
return log
}
func link(
options *config.Options,
timer *helpers.Timer,
log logger.Log,
fs fs.FS,
res resolver.Resolver,
inputFiles []graph.InputFile,
entryPoints []graph.EntryPoint,
uniqueKeyPrefix string,
reachableFiles []uint32,
dataForSourceMaps func() []dataForSourceMap,
) []graph.OutputFile {
timer.Begin("Link")
defer timer.End("Link")
log = wrappedLog(log)
timer.Begin("Clone linker graph")
c := linkerContext{
options: options,
timer: timer,
log: log,
fs: fs,
res: res,
dataForSourceMaps: dataForSourceMaps,
uniqueKeyPrefix: uniqueKeyPrefix,
uniqueKeyPrefixBytes: []byte(uniqueKeyPrefix),
graph: graph.CloneLinkerGraph(
inputFiles,
reachableFiles,
entryPoints,
options.CodeSplitting,
),
}
timer.End("Clone linker graph")
// Use a smaller version of these functions if we don't need profiler names
runtimeRepr := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr)
if c.options.ProfilerNames {
c.cjsRuntimeRef = runtimeRepr.AST.NamedExports["__commonJS"].Ref
c.esmRuntimeRef = runtimeRepr.AST.NamedExports["__esm"].Ref
} else {
c.cjsRuntimeRef = runtimeRepr.AST.NamedExports["__commonJSMin"].Ref
c.esmRuntimeRef = runtimeRepr.AST.NamedExports["__esmMin"].Ref
}
for _, entryPoint := range entryPoints {
if repr, ok := c.graph.Files[entryPoint.SourceIndex].InputFile.Repr.(*graph.JSRepr); ok {
// Loaders default to CommonJS when they are the entry point and the output
// format is not ESM-compatible since that avoids generating the ESM-to-CJS
// machinery.
if repr.AST.HasLazyExport && (c.options.Mode == config.ModePassThrough ||
(c.options.Mode == config.ModeConvertFormat && !c.options.OutputFormat.KeepES6ImportExportSyntax())) {
repr.AST.ExportsKind = js_ast.ExportsCommonJS
}
// Entry points with ES6 exports must generate an exports object when
// targeting non-ES6 formats. Note that the IIFE format only needs this
// when the global name is present, since that's the only way the exports
// can actually be observed externally.
if repr.AST.ExportKeyword.Len > 0 && (options.OutputFormat == config.FormatCommonJS ||
(options.OutputFormat == config.FormatIIFE && len(options.GlobalName) > 0)) {
repr.AST.UsesExportsRef = true
repr.Meta.ForceIncludeExportsForEntryPoint = true
}
}
}
// Allocate a new unbound symbol called "module" in case we need it later
if c.options.OutputFormat == config.FormatCommonJS {
c.unboundModuleRef = c.graph.GenerateNewSymbol(runtime.SourceIndex, js_ast.SymbolUnbound, "module")
} else {
c.unboundModuleRef = js_ast.InvalidRef
}
c.scanImportsAndExports()
// Stop now if there were errors
if c.log.HasErrors() {
return []graph.OutputFile{}
}
c.treeShakingAndCodeSplitting()
if c.options.Mode == config.ModePassThrough {
for _, entryPoint := range c.graph.EntryPoints() {
c.preventExportsFromBeingRenamed(entryPoint.SourceIndex)
}
}
chunks := c.computeChunks()
c.computeCrossChunkDependencies(chunks)
// Make sure calls to "js_ast.FollowSymbols()" in parallel goroutines after this
// won't hit concurrent map mutation hazards
js_ast.FollowAllSymbols(c.graph.Symbols)
return c.generateChunksInParallel(chunks)
}
// Currently the automatic chunk generation algorithm should by construction
// never generate chunks that import each other since files are allocated to
// chunks based on which entry points they are reachable from.
//
// This will change in the future when we allow manual chunk labels. But before
// we allow manual chunk labels, we'll need to rework module initialization to
// allow code splitting chunks to be lazily-initialized.
//
// Since that work hasn't been finished yet, cycles in the chunk import graph
// can cause initialization bugs. So let's forbid these cycles for now to guard
// against code splitting bugs that could cause us to generate buggy chunks.
func (c *linkerContext) enforceNoCyclicChunkImports(chunks []chunkInfo) {
var validate func(int, []int)
validate = func(chunkIndex int, path []int) {
for _, otherChunkIndex := range path {
if chunkIndex == otherChunkIndex {
c.log.Add(logger.Error, nil, logger.Range{}, "Internal error: generated chunks contain a circular import")
return
}
}
path = append(path, chunkIndex)
for _, chunkImport := range chunks[chunkIndex].crossChunkImports {
// Ignore cycles caused by dynamic "import()" expressions. These are fine
// because they don't necessarily cause initialization order issues and
// they don't indicate a bug in our chunk generation algorithm. They arise
// normally in real code (e.g. two files that import each other).
if chunkImport.importKind != ast.ImportDynamic {
validate(int(chunkImport.chunkIndex), path)
}
}
}
path := make([]int, 0, len(chunks))
for i := range chunks {
validate(i, path)
}
}
func (c *linkerContext) generateChunksInParallel(chunks []chunkInfo) []graph.OutputFile {
c.timer.Begin("Generate chunks")
defer c.timer.End("Generate chunks")
// Generate each chunk on a separate goroutine
generateWaitGroup := sync.WaitGroup{}
generateWaitGroup.Add(len(chunks))
for chunkIndex := range chunks {
switch chunks[chunkIndex].chunkRepr.(type) {
case *chunkReprJS:
go c.generateChunkJS(chunks, chunkIndex, &generateWaitGroup)
case *chunkReprCSS:
go c.generateChunkCSS(chunks, chunkIndex, &generateWaitGroup)
}
}
c.enforceNoCyclicChunkImports(chunks)
generateWaitGroup.Wait()
// Compute the final hashes of each chunk. This can technically be done in
// parallel but it probably doesn't matter so much because we're not hashing
// that much data.
visited := make([]uint32, len(chunks))
var finalBytes []byte
for chunkIndex := range chunks {
chunk := &chunks[chunkIndex]
var hashSubstitution *string
// Only wait for the hash if necessary
if config.HasPlaceholder(chunk.finalTemplate, config.HashPlaceholder) {
// Compute the final hash using the isolated hashes of the dependencies
hash := xxhash.New()
appendIsolatedHashesForImportedChunks(hash, chunks, uint32(chunkIndex), visited, ^uint32(chunkIndex))
finalBytes = hash.Sum(finalBytes[:0])
finalString := hashForFileName(finalBytes)
hashSubstitution = &finalString
}
// Render the last remaining placeholder in the template
chunk.finalRelPath = config.TemplateToString(config.SubstituteTemplate(chunk.finalTemplate, config.PathPlaceholders{
Hash: hashSubstitution,
}))
}
// Generate the final output files by joining file pieces together
c.timer.Begin("Generate final output files")
var resultsWaitGroup sync.WaitGroup
results := make([][]graph.OutputFile, len(chunks))
resultsWaitGroup.Add(len(chunks))
for chunkIndex, chunk := range chunks {
go func(chunkIndex int, chunk chunkInfo) {
var outputFiles []graph.OutputFile
// Each file may optionally contain additional files to be copied to the
// output directory. This is used by the "file" loader.
var commentPrefix string
var commentSuffix string
switch chunkRepr := chunk.chunkRepr.(type) {
case *chunkReprJS:
for _, sourceIndex := range chunkRepr.filesInChunkInOrder {
outputFiles = append(outputFiles, c.graph.Files[sourceIndex].InputFile.AdditionalFiles...)
}
commentPrefix = "//"
case *chunkReprCSS:
for _, sourceIndex := range chunkRepr.filesInChunkInOrder {
outputFiles = append(outputFiles, c.graph.Files[sourceIndex].InputFile.AdditionalFiles...)
}
commentPrefix = "/*"
commentSuffix = " */"
}
// Path substitution for the chunk itself
finalRelDir := c.fs.Dir(chunk.finalRelPath)
outputContentsJoiner, outputSourceMapShifts := c.substituteFinalPaths(chunks, chunk.intermediateOutput,
func(finalRelPathForImport string) string {
return c.pathBetweenChunks(finalRelDir, finalRelPathForImport)
})
// Generate the optional legal comments file for this chunk
if chunk.externalLegalComments != nil {
finalRelPathForLegalComments := chunk.finalRelPath + ".LEGAL.txt"
// Link the file to the legal comments
if c.options.LegalComments == config.LegalCommentsLinkedWithComment {
importPath := c.pathBetweenChunks(finalRelDir, finalRelPathForLegalComments)
importPath = strings.TrimPrefix(importPath, "./")
outputContentsJoiner.EnsureNewlineAtEnd()
outputContentsJoiner.AddString("/*! For license information please see ")
outputContentsJoiner.AddString(importPath)
outputContentsJoiner.AddString(" */\n")
}
// Write the external legal comments file
outputFiles = append(outputFiles, graph.OutputFile{
AbsPath: c.fs.Join(c.options.AbsOutputDir, finalRelPathForLegalComments),
Contents: chunk.externalLegalComments,
JSONMetadataChunk: fmt.Sprintf(
"{\n \"imports\": [],\n \"exports\": [],\n \"inputs\": {},\n \"bytes\": %d\n }", len(chunk.externalLegalComments)),
})
}
// Generate the optional source map for this chunk
if c.options.SourceMap != config.SourceMapNone && chunk.outputSourceMap.HasContent() {
outputSourceMap := chunk.outputSourceMap.Finalize(outputSourceMapShifts)
finalRelPathForSourceMap := chunk.finalRelPath + ".map"
// Potentially write a trailing source map comment
switch c.options.SourceMap {
case config.SourceMapLinkedWithComment:
importPath := c.pathBetweenChunks(finalRelDir, finalRelPathForSourceMap)
importPath = strings.TrimPrefix(importPath, "./")
outputContentsJoiner.EnsureNewlineAtEnd()
outputContentsJoiner.AddString(commentPrefix)
outputContentsJoiner.AddString("# sourceMappingURL=")
outputContentsJoiner.AddString(importPath)
outputContentsJoiner.AddString(commentSuffix)
outputContentsJoiner.AddString("\n")
case config.SourceMapInline, config.SourceMapInlineAndExternal:
outputContentsJoiner.EnsureNewlineAtEnd()
outputContentsJoiner.AddString(commentPrefix)
outputContentsJoiner.AddString("# sourceMappingURL=data:application/json;base64,")
outputContentsJoiner.AddString(base64.StdEncoding.EncodeToString(outputSourceMap))
outputContentsJoiner.AddString(commentSuffix)
outputContentsJoiner.AddString("\n")
}
// Potentially write the external source map file
switch c.options.SourceMap {
case config.SourceMapLinkedWithComment, config.SourceMapInlineAndExternal, config.SourceMapExternalWithoutComment:
outputFiles = append(outputFiles, graph.OutputFile{
AbsPath: c.fs.Join(c.options.AbsOutputDir, finalRelPathForSourceMap),
Contents: outputSourceMap,
JSONMetadataChunk: fmt.Sprintf(
"{\n \"imports\": [],\n \"exports\": [],\n \"inputs\": {},\n \"bytes\": %d\n }", len(outputSourceMap)),
})
}
}
// Finalize the output contents
outputContents := outputContentsJoiner.Done()
// Path substitution for the JSON metadata
var jsonMetadataChunk string
if c.options.NeedsMetafile {
jsonMetadataChunkPieces := c.breakOutputIntoPieces(chunk.jsonMetadataChunkCallback(len(outputContents)), uint32(len(chunks)))
jsonMetadataChunkBytes, _ := c.substituteFinalPaths(chunks, jsonMetadataChunkPieces, func(finalRelPathForImport string) string {
return c.res.PrettyPath(logger.Path{Text: c.fs.Join(c.options.AbsOutputDir, finalRelPathForImport), Namespace: "file"})
})
jsonMetadataChunk = string(jsonMetadataChunkBytes.Done())
}
// Generate the output file for this chunk
outputFiles = append(outputFiles, graph.OutputFile{
AbsPath: c.fs.Join(c.options.AbsOutputDir, chunk.finalRelPath),
Contents: outputContents,
JSONMetadataChunk: jsonMetadataChunk,
IsExecutable: chunk.isExecutable,
})
results[chunkIndex] = outputFiles
resultsWaitGroup.Done()
}(chunkIndex, chunk)
}
resultsWaitGroup.Wait()
c.timer.End("Generate final output files")
// Merge the output files from the different goroutines together in order
outputFilesLen := 0
for _, result := range results {
outputFilesLen += len(result)
}
outputFiles := make([]graph.OutputFile, 0, outputFilesLen)
for _, result := range results {
outputFiles = append(outputFiles, result...)
}
return outputFiles
}
// Given a set of output pieces (i.e. a buffer already divided into the spans
// between import paths), substitute the final import paths in and then join
// everything into a single byte buffer.
func (c *linkerContext) substituteFinalPaths(
chunks []chunkInfo,
intermediateOutput intermediateOutput,
modifyPath func(string) string,
) (j helpers.Joiner, shifts []sourcemap.SourceMapShift) {
// Optimization: If there can be no substitutions, just reuse the initial
// joiner that was used when generating the intermediate chunk output
// instead of creating another one and copying the whole file into it.
if intermediateOutput.pieces == nil {
return intermediateOutput.joiner, []sourcemap.SourceMapShift{{}}
}
var shift sourcemap.SourceMapShift
shifts = make([]sourcemap.SourceMapShift, 0, len(intermediateOutput.pieces))
shifts = append(shifts, shift)
for _, piece := range intermediateOutput.pieces {
var dataOffset sourcemap.LineColumnOffset
j.AddBytes(piece.data)
dataOffset.AdvanceBytes(piece.data)
shift.Before.Add(dataOffset)
shift.After.Add(dataOffset)
switch piece.kind {
case outputPieceAssetIndex:
file := c.graph.Files[piece.index]
if len(file.InputFile.AdditionalFiles) != 1 {
panic("Internal error")
}
relPath, _ := c.fs.Rel(c.options.AbsOutputDir, file.InputFile.AdditionalFiles[0].AbsPath)
// Make sure to always use forward slashes, even on Windows
relPath = strings.ReplaceAll(relPath, "\\", "/")
importPath := modifyPath(relPath)
j.AddString(importPath)
shift.Before.AdvanceString(file.InputFile.UniqueKeyForFileLoader)
shift.After.AdvanceString(importPath)
shifts = append(shifts, shift)
case outputPieceChunkIndex:
chunk := chunks[piece.index]
importPath := modifyPath(chunk.finalRelPath)
j.AddString(importPath)
shift.Before.AdvanceString(chunk.uniqueKey)
shift.After.AdvanceString(importPath)
shifts = append(shifts, shift)
}
}
return
}
func (c *linkerContext) pathBetweenChunks(fromRelDir string, toRelPath string) string {
// Join with the public path if it has been configured
if c.options.PublicPath != "" {
return joinWithPublicPath(c.options.PublicPath, toRelPath)
}
// Otherwise, return a relative path
relPath, ok := c.fs.Rel(fromRelDir, toRelPath)
if !ok {
c.log.Add(logger.Error, nil, logger.Range{},
fmt.Sprintf("Cannot traverse from directory %q to chunk %q", fromRelDir, toRelPath))
return ""
}
// Make sure to always use forward slashes, even on Windows
relPath = strings.ReplaceAll(relPath, "\\", "/")
// Make sure the relative path doesn't start with a name, since that could
// be interpreted as a package path instead of a relative path
if !strings.HasPrefix(relPath, "./") && !strings.HasPrefix(relPath, "../") {
relPath = "./" + relPath
}
return relPath
}
// Returns the path of this file relative to "outbase", which is then ready to
// be joined with the absolute output directory path. The directory and name
// components are returned separately for convenience.
func pathRelativeToOutbase(
inputFile *graph.InputFile,
options *config.Options,
fs fs.FS,
avoidIndex bool,
customFilePath string,
) (relDir string, baseName string) {
relDir = "/"
absPath := inputFile.Source.KeyPath.Text
if customFilePath != "" {
// Use the configured output path if present
absPath = customFilePath
if !fs.IsAbs(absPath) {
absPath = fs.Join(options.AbsOutputBase, absPath)
}
} else if inputFile.Source.KeyPath.Namespace != "file" {
// Come up with a path for virtual paths (i.e. non-file-system paths)
dir, base, _ := logger.PlatformIndependentPathDirBaseExt(absPath)
if avoidIndex && base == "index" {
_, base, _ = logger.PlatformIndependentPathDirBaseExt(dir)
}
baseName = sanitizeFilePathForVirtualModulePath(base)
return
} else {
// Heuristic: If the file is named something like "index.js", then use
// the name of the parent directory instead. This helps avoid the
// situation where many chunks are named "index" because of people
// dynamically-importing npm packages that make use of node's implicit
// "index" file name feature.
if avoidIndex {
base := fs.Base(absPath)
base = base[:len(base)-len(fs.Ext(base))]
if base == "index" {
absPath = fs.Dir(absPath)
}
}
}
// Try to get a relative path to the base directory
relPath, ok := fs.Rel(options.AbsOutputBase, absPath)
if !ok {
// This can fail in some situations such as on different drives on
// Windows. In that case we just use the file name.
baseName = fs.Base(absPath)
} else {
// Now we finally have a relative path
relDir = fs.Dir(relPath) + "/"
baseName = fs.Base(relPath)
// Use platform-independent slashes
relDir = strings.ReplaceAll(relDir, "\\", "/")
// Replace leading "../" so we don't try to write outside of the output
// directory. This normally can't happen because "AbsOutputBase" is
// automatically computed to contain all entry point files, but it can
// happen if someone sets it manually via the "outbase" API option.
//
// Note that we can't just strip any leading "../" because that could
// cause two separate entry point paths to collide. For example, there
// could be both "src/index.js" and "../src/index.js" as entry points.
dotDotCount := 0
for strings.HasPrefix(relDir[dotDotCount*3:], "../") {
dotDotCount++
}
if dotDotCount > 0 {
// The use of "_.._" here is somewhat arbitrary but it is unlikely to
// collide with a folder named by a human and it works on Windows
// (Windows doesn't like names that end with a "."). And not starting
// with a "." means that it will not be hidden on Unix.
relDir = strings.Repeat("_.._/", dotDotCount) + relDir[dotDotCount*3:]
}
for strings.HasSuffix(relDir, "/") {
relDir = relDir[:len(relDir)-1]
}
relDir = "/" + relDir
if strings.HasSuffix(relDir, "/.") {
relDir = relDir[:len(relDir)-1]
}
}
// Strip the file extension if the output path is an input file
if customFilePath == "" {
ext := fs.Ext(baseName)
baseName = baseName[:len(baseName)-len(ext)]
}
return
}
func (c *linkerContext) computeCrossChunkDependencies(chunks []chunkInfo) {
c.timer.Begin("Compute cross-chunk dependencies")
defer c.timer.End("Compute cross-chunk dependencies")
jsChunks := 0
for _, chunk := range chunks {
if _, ok := chunk.chunkRepr.(*chunkReprJS); ok {
jsChunks++
}
}
if jsChunks < 2 {
// No need to compute cross-chunk dependencies if there can't be any
return
}
type chunkMeta struct {
imports map[js_ast.Ref]bool
exports map[js_ast.Ref]bool
dynamicImports map[int]bool
}
chunkMetas := make([]chunkMeta, len(chunks))
// For each chunk, see what symbols it uses from other chunks. Do this in
// parallel because it's the most expensive part of this function.
waitGroup := sync.WaitGroup{}
waitGroup.Add(len(chunks))
for chunkIndex, chunk := range chunks {
go func(chunkIndex int, chunk chunkInfo) {
chunkMeta := &chunkMetas[chunkIndex]
imports := make(map[js_ast.Ref]bool)
chunkMeta.imports = imports
chunkMeta.exports = make(map[js_ast.Ref]bool)
// Go over each file in this chunk
for sourceIndex := range chunk.filesWithPartsInChunk {
// Go over each part in this file that's marked for inclusion in this chunk
switch repr := c.graph.Files[sourceIndex].InputFile.Repr.(type) {
case *graph.JSRepr:
for partIndex, partMeta := range repr.AST.Parts {
if !partMeta.IsLive {
continue
}
part := &repr.AST.Parts[partIndex]
// Rewrite external dynamic imports to point to the chunk for that entry point
for _, importRecordIndex := range part.ImportRecordIndices {
record := &repr.AST.ImportRecords[importRecordIndex]
if record.SourceIndex.IsValid() && c.isExternalDynamicImport(record, sourceIndex) {
otherChunkIndex := c.graph.Files[record.SourceIndex.GetIndex()].EntryPointChunkIndex
record.Path.Text = chunks[otherChunkIndex].uniqueKey
record.SourceIndex = ast.Index32{}
// Track this cross-chunk dynamic import so we make sure to
// include its hash when we're calculating the hashes of all
// dependencies of this chunk.
if int(otherChunkIndex) != chunkIndex {
if chunkMeta.dynamicImports == nil {
chunkMeta.dynamicImports = make(map[int]bool)
}
chunkMeta.dynamicImports[int(otherChunkIndex)] = true
}
}
}
// Remember what chunk each top-level symbol is declared in. Symbols
// with multiple declarations such as repeated "var" statements with
// the same name should already be marked as all being in a single
// chunk. In that case this will overwrite the same value below which
// is fine.
for _, declared := range part.DeclaredSymbols {
if declared.IsTopLevel {
c.graph.Symbols.Get(declared.Ref).ChunkIndex = ast.MakeIndex32(uint32(chunkIndex))
}
}
// Record each symbol used in this part. This will later be matched up
// with our map of which chunk a given symbol is declared in to
// determine if the symbol needs to be imported from another chunk.
for ref := range part.SymbolUses {
symbol := c.graph.Symbols.Get(ref)
// Ignore unbound symbols, which don't have declarations
if symbol.Kind == js_ast.SymbolUnbound {
continue
}
// Ignore symbols that are going to be replaced by undefined
if symbol.ImportItemStatus == js_ast.ImportItemMissing {
continue
}
// If this is imported from another file, follow the import
// reference and reference the symbol in that file instead
if importData, ok := repr.Meta.ImportsToBind[ref]; ok {
ref = importData.Ref
symbol = c.graph.Symbols.Get(ref)
} else if repr.Meta.Wrap == graph.WrapCJS && ref != repr.AST.WrapperRef {
// The only internal symbol that wrapped CommonJS files export
// is the wrapper itself.
continue
}
// If this is an ES6 import from a CommonJS file, it will become a
// property access off the namespace symbol instead of a bare
// identifier. In that case we want to pull in the namespace symbol
// instead. The namespace symbol stores the result of "require()".
if symbol.NamespaceAlias != nil {
ref = symbol.NamespaceAlias.NamespaceRef
}
// We must record this relationship even for symbols that are not
// imports. Due to code splitting, the definition of a symbol may
// be moved to a separate chunk than the use of a symbol even if
// the definition and use of that symbol are originally from the
// same source file.
imports[ref] = true
}
}
}
}
// Include the exports if this is an entry point chunk
if chunk.isEntryPoint {
if repr, ok := c.graph.Files[chunk.sourceIndex].InputFile.Repr.(*graph.JSRepr); ok {
if repr.Meta.Wrap != graph.WrapCJS {
for _, alias := range repr.Meta.SortedAndFilteredExportAliases {
export := repr.Meta.ResolvedExports[alias]
targetRef := export.Ref
// If this is an import, then target what the import points to
if importData, ok := c.graph.Files[export.SourceIndex].InputFile.Repr.(*graph.JSRepr).Meta.ImportsToBind[targetRef]; ok {
targetRef = importData.Ref
}
// If this is an ES6 import from a CommonJS file, it will become a
// property access off the namespace symbol instead of a bare
// identifier. In that case we want to pull in the namespace symbol
// instead. The namespace symbol stores the result of "require()".
if symbol := c.graph.Symbols.Get(targetRef); symbol.NamespaceAlias != nil {
targetRef = symbol.NamespaceAlias.NamespaceRef
}
imports[targetRef] = true
}
}
// Ensure "exports" is included if the current output format needs it
if repr.Meta.ForceIncludeExportsForEntryPoint {
imports[repr.AST.ExportsRef] = true
}
// Include the wrapper if present
if repr.Meta.Wrap != graph.WrapNone {
imports[repr.AST.WrapperRef] = true
}
}
}
waitGroup.Done()
}(chunkIndex, chunk)
}
waitGroup.Wait()
// Mark imported symbols as exported in the chunk from which they are declared
for chunkIndex := range chunks {
chunk := &chunks[chunkIndex]
chunkRepr, ok := chunk.chunkRepr.(*chunkReprJS)
if !ok {
continue
}
chunkMeta := chunkMetas[chunkIndex]
// Find all uses in this chunk of symbols from other chunks
chunkRepr.importsFromOtherChunks = make(map[uint32]crossChunkImportItemArray)
for importRef := range chunkMeta.imports {
// Ignore uses that aren't top-level symbols
if otherChunkIndex := c.graph.Symbols.Get(importRef).ChunkIndex; otherChunkIndex.IsValid() {
if otherChunkIndex := otherChunkIndex.GetIndex(); otherChunkIndex != uint32(chunkIndex) {
chunkRepr.importsFromOtherChunks[otherChunkIndex] =
append(chunkRepr.importsFromOtherChunks[otherChunkIndex], crossChunkImportItem{ref: importRef})
chunkMetas[otherChunkIndex].exports[importRef] = true
}
}
}
// If this is an entry point, make sure we import all chunks belonging to
// this entry point, even if there are no imports. We need to make sure
// these chunks are evaluated for their side effects too.
if chunk.isEntryPoint {
for otherChunkIndex, otherChunk := range chunks {
if _, ok := otherChunk.chunkRepr.(*chunkReprJS); ok && chunkIndex != otherChunkIndex && otherChunk.entryBits.HasBit(chunk.entryPointBit) {
imports := chunkRepr.importsFromOtherChunks[uint32(otherChunkIndex)]
chunkRepr.importsFromOtherChunks[uint32(otherChunkIndex)] = imports
}
}
}
// Make sure we also track dynamic cross-chunk imports. These need to be
// tracked so we count them as dependencies of this chunk for the purpose
// of hash calculation.
if chunkMeta.dynamicImports != nil {
sortedDynamicImports := make([]int, 0, len(chunkMeta.dynamicImports))
for chunkIndex := range chunkMeta.dynamicImports {
sortedDynamicImports = append(sortedDynamicImports, chunkIndex)
}
sort.Ints(sortedDynamicImports)
for _, chunkIndex := range sortedDynamicImports {
chunk.crossChunkImports = append(chunk.crossChunkImports, chunkImport{
importKind: ast.ImportDynamic,
chunkIndex: uint32(chunkIndex),
})
}
}
}
// Generate cross-chunk exports. These must be computed before cross-chunk
// imports because of export alias renaming, which must consider all export
// aliases simultaneously to avoid collisions.
for chunkIndex := range chunks {
chunk := &chunks[chunkIndex]
chunkRepr, ok := chunk.chunkRepr.(*chunkReprJS)
if !ok {
continue
}
chunkRepr.exportsToOtherChunks = make(map[js_ast.Ref]string)
switch c.options.OutputFormat {
case config.FormatESModule:
r := renamer.ExportRenamer{}
var items []js_ast.ClauseItem
for _, export := range c.sortedCrossChunkExportItems(chunkMetas[chunkIndex].exports) {
var alias string
if c.options.MinifyIdentifiers {
alias = r.NextMinifiedName()
} else {
alias = r.NextRenamedName(c.graph.Symbols.Get(export.Ref).OriginalName)
}
items = append(items, js_ast.ClauseItem{Name: js_ast.LocRef{Ref: export.Ref}, Alias: alias})
chunkRepr.exportsToOtherChunks[export.Ref] = alias
}
if len(items) > 0 {
chunkRepr.crossChunkSuffixStmts = []js_ast.Stmt{{Data: &js_ast.SExportClause{
Items: items,
}}}
}
default:
panic("Internal error")
}
}
// Generate cross-chunk imports. These must be computed after cross-chunk
// exports because the export aliases must already be finalized so they can
// be embedded in the generated import statements.
for chunkIndex := range chunks {
chunk := &chunks[chunkIndex]
chunkRepr, ok := chunk.chunkRepr.(*chunkReprJS)
if !ok {
continue
}
var crossChunkPrefixStmts []js_ast.Stmt
for _, crossChunkImport := range c.sortedCrossChunkImports(chunks, chunkRepr.importsFromOtherChunks) {
switch c.options.OutputFormat {
case config.FormatESModule:
var items []js_ast.ClauseItem
for _, item := range crossChunkImport.sortedImportItems {
items = append(items, js_ast.ClauseItem{Name: js_ast.LocRef{Ref: item.ref}, Alias: item.exportAlias})
}
importRecordIndex := uint32(len(chunk.crossChunkImports))
chunk.crossChunkImports = append(chunk.crossChunkImports, chunkImport{
importKind: ast.ImportStmt,
chunkIndex: crossChunkImport.chunkIndex,
})
if len(items) > 0 {
// "import {a, b} from './chunk.js'"
crossChunkPrefixStmts = append(crossChunkPrefixStmts, js_ast.Stmt{Data: &js_ast.SImport{
Items: &items,
ImportRecordIndex: importRecordIndex,
}})
} else {
// "import './chunk.js'"
crossChunkPrefixStmts = append(crossChunkPrefixStmts, js_ast.Stmt{Data: &js_ast.SImport{
ImportRecordIndex: importRecordIndex,
}})
}
default:
panic("Internal error")
}
}
chunkRepr.crossChunkPrefixStmts = crossChunkPrefixStmts
}
}
type crossChunkImport struct {
chunkIndex uint32
sortedImportItems crossChunkImportItemArray
}
// This type is just so we can use Go's native sort function
type crossChunkImportArray []crossChunkImport
func (a crossChunkImportArray) Len() int { return len(a) }
func (a crossChunkImportArray) Swap(i int, j int) { a[i], a[j] = a[j], a[i] }
func (a crossChunkImportArray) Less(i int, j int) bool {
return a[i].chunkIndex < a[j].chunkIndex
}
// Sort cross-chunk imports by chunk name for determinism
func (c *linkerContext) sortedCrossChunkImports(chunks []chunkInfo, importsFromOtherChunks map[uint32]crossChunkImportItemArray) crossChunkImportArray {
result := make(crossChunkImportArray, 0, len(importsFromOtherChunks))
for otherChunkIndex, importItems := range importsFromOtherChunks {
// Sort imports from a single chunk by alias for determinism
otherChunk := &chunks[otherChunkIndex]
exportsToOtherChunks := otherChunk.chunkRepr.(*chunkReprJS).exportsToOtherChunks
for i, item := range importItems {
importItems[i].exportAlias = exportsToOtherChunks[item.ref]
}
sort.Sort(importItems)
result = append(result, crossChunkImport{
chunkIndex: otherChunkIndex,
sortedImportItems: importItems,
})
}
sort.Sort(result)
return result
}
type crossChunkImportItem struct {
ref js_ast.Ref
exportAlias string
}
// This type is just so we can use Go's native sort function
type crossChunkImportItemArray []crossChunkImportItem
func (a crossChunkImportItemArray) Len() int { return len(a) }
func (a crossChunkImportItemArray) Swap(i int, j int) { a[i], a[j] = a[j], a[i] }
func (a crossChunkImportItemArray) Less(i int, j int) bool {
return a[i].exportAlias < a[j].exportAlias
}
// The sort order here is arbitrary but needs to be consistent between builds.
// The InnerIndex should be stable because the parser for a single file is
// single-threaded and deterministically assigns out InnerIndex values
// sequentially. But the SourceIndex should be unstable because the main thread
// assigns out source index values sequentially to newly-discovered dependencies
// in a multi-threaded producer/consumer relationship. So instead we use the
// index of the source in the DFS order over all entry points for stability.
type stableRef struct {
StableSourceIndex uint32
Ref js_ast.Ref
}
// This type is just so we can use Go's native sort function
type stableRefArray []stableRef
func (a stableRefArray) Len() int { return len(a) }
func (a stableRefArray) Swap(i int, j int) { a[i], a[j] = a[j], a[i] }
func (a stableRefArray) Less(i int, j int) bool {
ai, aj := a[i], a[j]
return ai.StableSourceIndex < aj.StableSourceIndex ||
(ai.StableSourceIndex == aj.StableSourceIndex && ai.Ref.InnerIndex < aj.Ref.InnerIndex)
}
// Sort cross-chunk exports by chunk name for determinism
func (c *linkerContext) sortedCrossChunkExportItems(exportRefs map[js_ast.Ref]bool) stableRefArray {
result := make(stableRefArray, 0, len(exportRefs))
for ref := range exportRefs {
result = append(result, stableRef{
StableSourceIndex: c.graph.StableSourceIndices[ref.SourceIndex],
Ref: ref,
})
}
sort.Sort(result)
return result
}
func (c *linkerContext) scanImportsAndExports() {
c.timer.Begin("Scan imports and exports")
defer c.timer.End("Scan imports and exports")
// Step 1: Figure out what modules must be CommonJS
c.timer.Begin("Step 1")
for _, sourceIndex := range c.graph.ReachableFiles {
file := &c.graph.Files[sourceIndex]
switch repr := file.InputFile.Repr.(type) {
case *graph.CSSRepr:
// Inline URLs for non-CSS files into the CSS file
var additionalFiles []graph.OutputFile
for importRecordIndex := range repr.AST.ImportRecords {
if record := &repr.AST.ImportRecords[importRecordIndex]; record.SourceIndex.IsValid() {
otherFile := &c.graph.Files[record.SourceIndex.GetIndex()]
if otherRepr, ok := otherFile.InputFile.Repr.(*graph.JSRepr); ok {
record.Path.Text = otherRepr.AST.URLForCSS
record.Path.Namespace = ""
record.SourceIndex = ast.Index32{}
// Copy the additional files to the output directory
additionalFiles = append(additionalFiles, otherFile.InputFile.AdditionalFiles...)
}
}
}
file.InputFile.AdditionalFiles = additionalFiles
case *graph.JSRepr:
for importRecordIndex := range repr.AST.ImportRecords {
record := &repr.AST.ImportRecords[importRecordIndex]
if !record.SourceIndex.IsValid() {
continue
}
otherFile := &c.graph.Files[record.SourceIndex.GetIndex()]
otherRepr := otherFile.InputFile.Repr.(*graph.JSRepr)
switch record.Kind {
case ast.ImportStmt:
// Importing using ES6 syntax from a file without any ES6 syntax
// causes that module to be considered CommonJS-style, even if it
// doesn't have any CommonJS exports.
//
// That means the ES6 imports will become undefined instead of
// causing errors. This is for compatibility with older CommonJS-
// style bundlers.
//
// We emit a warning in this case but try to avoid turning the module
// into a CommonJS module if possible. This is possible with named
// imports (the module stays an ECMAScript module but the imports are
// rewritten with undefined) but is not possible with star or default
// imports:
//
// import * as ns from './empty-file'
// import defVal from './empty-file'
// console.log(ns, defVal)
//
// In that case the module *is* considered a CommonJS module because
// the namespace object must be created.
if (record.ContainsImportStar || record.ContainsDefaultAlias) && otherRepr.AST.ExportsKind == js_ast.ExportsNone && !otherRepr.AST.HasLazyExport {
otherRepr.Meta.Wrap = graph.WrapCJS
otherRepr.AST.ExportsKind = js_ast.ExportsCommonJS
}
case ast.ImportRequire:
// Files that are imported with require() must be CommonJS modules
if otherRepr.AST.ExportsKind == js_ast.ExportsESM {
otherRepr.Meta.Wrap = graph.WrapESM
} else {
otherRepr.Meta.Wrap = graph.WrapCJS
otherRepr.AST.ExportsKind = js_ast.ExportsCommonJS
}
case ast.ImportDynamic:
if !c.options.CodeSplitting {
// If we're not splitting, then import() is just a require() that
// returns a promise, so the imported file must be a CommonJS module
if otherRepr.AST.ExportsKind == js_ast.ExportsESM {
otherRepr.Meta.Wrap = graph.WrapESM
} else {
otherRepr.Meta.Wrap = graph.WrapCJS
otherRepr.AST.ExportsKind = js_ast.ExportsCommonJS
}
}
}
}
// If the output format doesn't have an implicit CommonJS wrapper, any file
// that uses CommonJS features will need to be wrapped, even though the
// resulting wrapper won't be invoked by other files. An exception is made
// for entry point files in CommonJS format (or when in pass-through mode).
if repr.AST.ExportsKind == js_ast.ExportsCommonJS && (!file.IsEntryPoint() ||
c.options.OutputFormat == config.FormatIIFE || c.options.OutputFormat == config.FormatESModule) {
repr.Meta.Wrap = graph.WrapCJS
}
}
}
c.timer.End("Step 1")
// Step 2: Propagate dynamic export status for export star statements that
// are re-exports from a module whose exports are not statically analyzable.
// In this case the export star must be evaluated at run time instead of at
// bundle time.
c.timer.Begin("Step 2")
for _, sourceIndex := range c.graph.ReachableFiles {
repr, ok := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
if !ok {
continue
}
if repr.Meta.Wrap != graph.WrapNone {
c.recursivelyWrapDependencies(sourceIndex)
}
if len(repr.AST.ExportStarImportRecords) > 0 {
visited := make(map[uint32]bool)
c.hasDynamicExportsDueToExportStar(sourceIndex, visited)
}
// Even if the output file is CommonJS-like, we may still need to wrap
// CommonJS-style files. Any file that imports a CommonJS-style file will
// cause that file to need to be wrapped. This is because the import
// method, whatever it is, will need to invoke the wrapper. Note that
// this can include entry points (e.g. an entry point that imports a file
// that imports that entry point).
for _, record := range repr.AST.ImportRecords {
if record.SourceIndex.IsValid() {
otherRepr := c.graph.Files[record.SourceIndex.GetIndex()].InputFile.Repr.(*graph.JSRepr)
if otherRepr.AST.ExportsKind == js_ast.ExportsCommonJS {
c.recursivelyWrapDependencies(record.SourceIndex.GetIndex())
}
}
}
}
c.timer.End("Step 2")
// Step 3: Resolve "export * from" statements. This must be done after we
// discover all modules that can have dynamic exports because export stars
// are ignored for those modules.
c.timer.Begin("Step 3")
exportStarStack := make([]uint32, 0, 32)
for _, sourceIndex := range c.graph.ReachableFiles {
repr, ok := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
if !ok {
continue
}
// Expression-style loaders defer code generation until linking. Code
// generation is done here because at this point we know that the
// "ExportsKind" field has its final value and will not be changed.
if repr.AST.HasLazyExport {
c.generateCodeForLazyExport(sourceIndex)
}
// Propagate exports for export star statements
if len(repr.AST.ExportStarImportRecords) > 0 {
c.addExportsForExportStar(repr.Meta.ResolvedExports, sourceIndex, exportStarStack)
}
// Also add a special export so import stars can bind to it. This must be
// done in this step because it must come after CommonJS module discovery
// but before matching imports with exports.
repr.Meta.ResolvedExportStar = &graph.ExportData{
Ref: repr.AST.ExportsRef,
SourceIndex: sourceIndex,
}
}
c.timer.End("Step 3")
// Step 4: Match imports with exports. This must be done after we process all
// export stars because imports can bind to export star re-exports.
c.timer.Begin("Step 4")
for _, sourceIndex := range c.graph.ReachableFiles {
file := &c.graph.Files[sourceIndex]
repr, ok := file.InputFile.Repr.(*graph.JSRepr)
if !ok {
continue
}
if len(repr.AST.NamedImports) > 0 {
c.matchImportsWithExportsForFile(uint32(sourceIndex))
}
// If we're exporting as CommonJS and this file was originally CommonJS,
// then we'll be using the actual CommonJS "exports" and/or "module"
// symbols. In that case make sure to mark them as such so they don't
// get minified.
if file.IsEntryPoint() && repr.AST.ExportsKind == js_ast.ExportsCommonJS && repr.Meta.Wrap == graph.WrapNone &&
(c.options.OutputFormat == config.FormatPreserve || c.options.OutputFormat == config.FormatCommonJS) {
exportsRef := js_ast.FollowSymbols(c.graph.Symbols, repr.AST.ExportsRef)
moduleRef := js_ast.FollowSymbols(c.graph.Symbols, repr.AST.ModuleRef)
c.graph.Symbols.Get(exportsRef).Kind = js_ast.SymbolUnbound
c.graph.Symbols.Get(moduleRef).Kind = js_ast.SymbolUnbound
} else if repr.Meta.ForceIncludeExportsForEntryPoint || repr.AST.ExportsKind != js_ast.ExportsCommonJS {
repr.Meta.NeedsExportsVariable = true
}
// Create the wrapper part for wrapped files. This is needed by a later step.
c.createWrapperForFile(uint32(sourceIndex))
}
c.timer.End("Step 4")
// Step 5: Create namespace exports for every file. This is always necessary
// for CommonJS files, and is also necessary for other files if they are
// imported using an import star statement.
c.timer.Begin("Step 5")
waitGroup := sync.WaitGroup{}
for _, sourceIndex := range c.graph.ReachableFiles {
repr, ok := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
if !ok {
continue
}
// This is the slowest step and is also parallelizable, so do this in parallel.
waitGroup.Add(1)
go func(sourceIndex uint32, repr *graph.JSRepr) {
// Now that all exports have been resolved, sort and filter them to create
// something we can iterate over later.
aliases := make([]string, 0, len(repr.Meta.ResolvedExports))
nextAlias:
for alias, export := range repr.Meta.ResolvedExports {
// Re-exporting multiple symbols with the same name causes an ambiguous
// export. These names cannot be used and should not end up in generated code.
otherRepr := c.graph.Files[export.SourceIndex].InputFile.Repr.(*graph.JSRepr)
if len(export.PotentiallyAmbiguousExportStarRefs) > 0 {
mainRef := export.Ref
if imported, ok := otherRepr.Meta.ImportsToBind[export.Ref]; ok {
mainRef = imported.Ref
}
for _, ambiguousExport := range export.PotentiallyAmbiguousExportStarRefs {
ambiguousRepr := c.graph.Files[ambiguousExport.SourceIndex].InputFile.Repr.(*graph.JSRepr)
ambiguousRef := ambiguousExport.Ref
if imported, ok := ambiguousRepr.Meta.ImportsToBind[ambiguousExport.Ref]; ok {
ambiguousRef = imported.Ref
}
if mainRef != ambiguousRef {
continue nextAlias
}
}
}
// Ignore re-exported imports in TypeScript files that failed to be
// resolved. These are probably just type-only imports so the best thing to
// do is to silently omit them from the export list.
if otherRepr.Meta.IsProbablyTypeScriptType[export.Ref] {
continue
}
aliases = append(aliases, alias)
}
sort.Strings(aliases)
repr.Meta.SortedAndFilteredExportAliases = aliases
// Export creation uses "sortedAndFilteredExportAliases" so this must
// come second after we fill in that array
c.createExportsForFile(uint32(sourceIndex))
waitGroup.Done()
}(sourceIndex, repr)
}
waitGroup.Wait()
c.timer.End("Step 5")
// Step 6: Bind imports to exports. This adds non-local dependencies on the
// parts that declare the export to all parts that use the import. Also
// generate wrapper parts for wrapped files.
c.timer.Begin("Step 6")
for _, sourceIndex := range c.graph.ReachableFiles {
file := &c.graph.Files[sourceIndex]
repr, ok := file.InputFile.Repr.(*graph.JSRepr)
if !ok {
continue
}
// Pre-generate symbols for re-exports CommonJS symbols in case they
// are necessary later. This is done now because the symbols map cannot be
// mutated later due to parallelism.
if file.IsEntryPoint() && c.options.OutputFormat == config.FormatESModule {
copies := make([]js_ast.Ref, len(repr.Meta.SortedAndFilteredExportAliases))
for i, alias := range repr.Meta.SortedAndFilteredExportAliases {
copies[i] = c.graph.GenerateNewSymbol(sourceIndex, js_ast.SymbolOther, "export_"+alias)
}
repr.Meta.CJSExportCopies = copies
}
// Use "init_*" for ESM wrappers instead of "require_*"
if repr.Meta.Wrap == graph.WrapESM {
c.graph.Symbols.Get(repr.AST.WrapperRef).OriginalName = "init_" + file.InputFile.Source.IdentifierName
}
// If this isn't CommonJS, then rename the unused "exports" and "module"
// variables to avoid them causing the identically-named variables in
// actual CommonJS files from being renamed. This is purely about
// aesthetics and is not about correctness. This is done here because by
// this point, we know the CommonJS status will not change further.
if repr.Meta.Wrap != graph.WrapCJS && repr.AST.ExportsKind != js_ast.ExportsCommonJS {
name := file.InputFile.Source.IdentifierName
c.graph.Symbols.Get(repr.AST.ExportsRef).OriginalName = name + "_exports"
c.graph.Symbols.Get(repr.AST.ModuleRef).OriginalName = name + "_module"
}
// Include the "__export" symbol from the runtime if it was used in the
// previous step. The previous step can't do this because it's running in
// parallel and can't safely mutate the "importsToBind" map of another file.
if repr.Meta.NeedsExportSymbolFromRuntime {
runtimeRepr := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr)
exportRef := runtimeRepr.AST.ModuleScope.Members["__export"].Ref
c.graph.GenerateSymbolImportAndUse(sourceIndex, js_ast.NSExportPartIndex, exportRef, 1, runtime.SourceIndex)
}
for importRef, importData := range repr.Meta.ImportsToBind {
resolvedRepr := c.graph.Files[importData.SourceIndex].InputFile.Repr.(*graph.JSRepr)
partsDeclaringSymbol := resolvedRepr.TopLevelSymbolToParts(importData.Ref)
for _, partIndex := range repr.AST.NamedImports[importRef].LocalPartsWithUses {
part := &repr.AST.Parts[partIndex]
// Depend on the file containing the imported symbol
for _, resolvedPartIndex := range partsDeclaringSymbol {
part.Dependencies = append(part.Dependencies, js_ast.Dependency{
SourceIndex: importData.SourceIndex,
PartIndex: resolvedPartIndex,
})
}
// Also depend on any files that re-exported this symbol in between the
// file containing the import and the file containing the imported symbol
part.Dependencies = append(part.Dependencies, importData.ReExports...)
}
// Merge these symbols so they will share the same name
js_ast.MergeSymbols(c.graph.Symbols, importRef, importData.Ref)
}
// If this is an entry point, depend on all exports so they are included
if file.IsEntryPoint() {
var dependencies []js_ast.Dependency
for _, alias := range repr.Meta.SortedAndFilteredExportAliases {
export := repr.Meta.ResolvedExports[alias]
targetSourceIndex := export.SourceIndex
targetRef := export.Ref
// If this is an import, then target what the import points to
targetRepr := c.graph.Files[targetSourceIndex].InputFile.Repr.(*graph.JSRepr)
if importData, ok := targetRepr.Meta.ImportsToBind[targetRef]; ok {
targetSourceIndex = importData.SourceIndex
targetRef = importData.Ref
targetRepr = c.graph.Files[targetSourceIndex].InputFile.Repr.(*graph.JSRepr)
dependencies = append(dependencies, importData.ReExports...)
}
// Pull in all declarations of this symbol
for _, partIndex := range targetRepr.TopLevelSymbolToParts(targetRef) {
dependencies = append(dependencies, js_ast.Dependency{
SourceIndex: targetSourceIndex,
PartIndex: partIndex,
})
}
}
// Ensure "exports" is included if the current output format needs it
if repr.Meta.ForceIncludeExportsForEntryPoint {
dependencies = append(dependencies, js_ast.Dependency{
SourceIndex: sourceIndex,
PartIndex: js_ast.NSExportPartIndex,
})
}
// Include the wrapper if present
if repr.Meta.Wrap != graph.WrapNone {
dependencies = append(dependencies, js_ast.Dependency{
SourceIndex: sourceIndex,
PartIndex: repr.Meta.WrapperPartIndex.GetIndex(),
})
}
// Represent these constraints with a dummy part
entryPointPartIndex := c.graph.AddPartToFile(sourceIndex, js_ast.Part{
Dependencies: dependencies,
CanBeRemovedIfUnused: false,
})
repr.Meta.EntryPointPartIndex = ast.MakeIndex32(entryPointPartIndex)
// Pull in the "__toCommonJS" symbol if we need it due to being an entry point
if repr.Meta.ForceIncludeExportsForEntryPoint {
c.graph.GenerateRuntimeSymbolImportAndUse(sourceIndex, entryPointPartIndex, "__toCommonJS", 1)
}
}
// Encode import-specific constraints in the dependency graph
for partIndex, part := range repr.AST.Parts {
toESMUses := uint32(0)
toCommonJSUses := uint32(0)
runtimeRequireUses := uint32(0)
// Imports of wrapped files must depend on the wrapper
for _, importRecordIndex := range part.ImportRecordIndices {
record := &repr.AST.ImportRecords[importRecordIndex]
// Don't follow external imports (this includes import() expressions)
if !record.SourceIndex.IsValid() || c.isExternalDynamicImport(record, sourceIndex) {
// This is an external import. Check if it will be a "require()" call.
if record.Kind == ast.ImportRequire || !c.options.OutputFormat.KeepES6ImportExportSyntax() ||
(record.Kind == ast.ImportDynamic && c.options.UnsupportedJSFeatures.Has(compat.DynamicImport)) {
// We should use "__require" instead of "require" if we're not
// generating a CommonJS output file, since it won't exist otherwise
if config.ShouldCallRuntimeRequire(c.options.Mode, c.options.OutputFormat) {
record.CallRuntimeRequire = true
runtimeRequireUses++
}
// It needs the "__toESM" wrapper if it wasn't originally a
// CommonJS import (i.e. it wasn't a "require()" call).
if record.Kind != ast.ImportRequire {
record.WrapWithToESM = true
toESMUses++
}
}
continue
}
otherSourceIndex := record.SourceIndex.GetIndex()
otherRepr := c.graph.Files[otherSourceIndex].InputFile.Repr.(*graph.JSRepr)
if otherRepr.Meta.Wrap != graph.WrapNone {
// Depend on the automatically-generated require wrapper symbol
wrapperRef := otherRepr.AST.WrapperRef
c.graph.GenerateSymbolImportAndUse(sourceIndex, uint32(partIndex), wrapperRef, 1, otherSourceIndex)
// This is an ES6 import of a CommonJS module, so it needs the
// "__toESM" wrapper as long as it's not a bare "require()"
if record.Kind != ast.ImportRequire && otherRepr.AST.ExportsKind == js_ast.ExportsCommonJS {
record.WrapWithToESM = true
toESMUses++
}
// If this is an ESM wrapper, also depend on the exports object
// since the final code will contain an inline reference to it.
// This must be done for "require()" and "import()" expressions
// but does not need to be done for "import" statements since
// those just cause us to reference the exports directly.
if otherRepr.Meta.Wrap == graph.WrapESM && record.Kind != ast.ImportStmt {
c.graph.GenerateSymbolImportAndUse(sourceIndex, uint32(partIndex), otherRepr.AST.ExportsRef, 1, otherSourceIndex)
// If this is a "require()" call, then we should add the
// "__esModule" marker to behave as if the module was converted
// from ESM to CommonJS. This is done via a wrapper instead of
// by modifying the exports object itself because the same ES
// module may be simultaneously imported and required, and the
// importing code should not see "__esModule" while the requiring
// code should see "__esModule". This is an extremely complex
// and subtle set of bundler interop issues. See for example
// https://github.com/evanw/esbuild/issues/1591.
if record.Kind == ast.ImportRequire {
record.WrapWithToCJS = true
toCommonJSUses++
}
}
} else if record.Kind == ast.ImportStmt && otherRepr.AST.ExportsKind == js_ast.ExportsESMWithDynamicFallback {
// This is an import of a module that has a dynamic export fallback
// object. In that case we need to depend on that object in case
// something ends up needing to use it later. This could potentially
// be omitted in some cases with more advanced analysis if this
// dynamic export fallback object doesn't end up being needed.
c.graph.GenerateSymbolImportAndUse(sourceIndex, uint32(partIndex), otherRepr.AST.ExportsRef, 1, otherSourceIndex)
}
}
// If there's an ES6 import of a non-ES6 module, then we're going to need the
// "__toESM" symbol from the runtime to wrap the result of "require()"
c.graph.GenerateRuntimeSymbolImportAndUse(sourceIndex, uint32(partIndex), "__toESM", toESMUses)
// If there's a CommonJS require of an ES6 module, then we're going to need the
// "__toCommonJS" symbol from the runtime to wrap the exports object
c.graph.GenerateRuntimeSymbolImportAndUse(sourceIndex, uint32(partIndex), "__toCommonJS", toCommonJSUses)
// If there are unbundled calls to "require()" and we're not generating
// code for node, then substitute a "__require" wrapper for "require".
c.graph.GenerateRuntimeSymbolImportAndUse(sourceIndex, uint32(partIndex), "__require", runtimeRequireUses)
// If there's an ES6 export star statement of a non-ES6 module, then we're
// going to need the "__reExport" symbol from the runtime
reExportUses := uint32(0)
for _, importRecordIndex := range repr.AST.ExportStarImportRecords {
record := &repr.AST.ImportRecords[importRecordIndex]
// Is this export star evaluated at run time?
happensAtRunTime := !record.SourceIndex.IsValid() && (!file.IsEntryPoint() || !c.options.OutputFormat.KeepES6ImportExportSyntax())
if record.SourceIndex.IsValid() {
otherSourceIndex := record.SourceIndex.GetIndex()
otherRepr := c.graph.Files[otherSourceIndex].InputFile.Repr.(*graph.JSRepr)
if otherSourceIndex != sourceIndex && otherRepr.AST.ExportsKind.IsDynamic() {
happensAtRunTime = true
}
if otherRepr.AST.ExportsKind == js_ast.ExportsESMWithDynamicFallback {
// This looks like "__reExport(exports_a, exports_b)". Make sure to
// pull in the "exports_b" symbol into this export star. This matters
// in code splitting situations where the "export_b" symbol might live
// in a different chunk than this export star.
c.graph.GenerateSymbolImportAndUse(sourceIndex, uint32(partIndex), otherRepr.AST.ExportsRef, 1, otherSourceIndex)
}
}
if happensAtRunTime {
// Depend on this file's "exports" object for the first argument to "__reExport"
c.graph.GenerateSymbolImportAndUse(sourceIndex, uint32(partIndex), repr.AST.ExportsRef, 1, sourceIndex)
record.CallsRunTimeReExportFn = true
repr.AST.UsesExportsRef = true
reExportUses++
}
}
c.graph.GenerateRuntimeSymbolImportAndUse(sourceIndex, uint32(partIndex), "__reExport", reExportUses)
}
}
c.timer.End("Step 6")
}
func (c *linkerContext) generateCodeForLazyExport(sourceIndex uint32) {
file := &c.graph.Files[sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
// Grab the lazy expression
if len(repr.AST.Parts) < 1 {
panic("Internal error")
}
part := &repr.AST.Parts[1]
if len(part.Stmts) != 1 {
panic("Internal error")
}
lazy, ok := part.Stmts[0].Data.(*js_ast.SLazyExport)
if !ok {
panic("Internal error")
}
// Use "module.exports = value" for CommonJS-style modules
if repr.AST.ExportsKind == js_ast.ExportsCommonJS {
part.Stmts = []js_ast.Stmt{js_ast.AssignStmt(
js_ast.Expr{Loc: lazy.Value.Loc, Data: &js_ast.EDot{
Target: js_ast.Expr{Loc: lazy.Value.Loc, Data: &js_ast.EIdentifier{Ref: repr.AST.ModuleRef}},
Name: "exports",
NameLoc: lazy.Value.Loc,
}},
lazy.Value,
)}
c.graph.GenerateSymbolImportAndUse(sourceIndex, 0, repr.AST.ModuleRef, 1, sourceIndex)
return
}
// Otherwise, generate ES6 export statements. These are added as additional
// parts so they can be tree shaken individually.
part.Stmts = nil
type prevExport struct {
ref js_ast.Ref
partIndex uint32
}
generateExport := func(name string, alias string, value js_ast.Expr) prevExport {
// Generate a new symbol
ref := c.graph.GenerateNewSymbol(sourceIndex, js_ast.SymbolOther, name)
// Generate an ES6 export
var stmt js_ast.Stmt
if alias == "default" {
stmt = js_ast.Stmt{Loc: value.Loc, Data: &js_ast.SExportDefault{
DefaultName: js_ast.LocRef{Loc: value.Loc, Ref: ref},
Value: js_ast.Stmt{Loc: value.Loc, Data: &js_ast.SExpr{Value: value}},
}}
} else {
stmt = js_ast.Stmt{Loc: value.Loc, Data: &js_ast.SLocal{
IsExport: true,
Decls: []js_ast.Decl{{
Binding: js_ast.Binding{Loc: value.Loc, Data: &js_ast.BIdentifier{Ref: ref}},
ValueOrNil: value,
}},
}}
}
// Link the export into the graph for tree shaking
partIndex := c.graph.AddPartToFile(sourceIndex, js_ast.Part{
Stmts: []js_ast.Stmt{stmt},
DeclaredSymbols: []js_ast.DeclaredSymbol{{Ref: ref, IsTopLevel: true}},
CanBeRemovedIfUnused: true,
})
c.graph.GenerateSymbolImportAndUse(sourceIndex, partIndex, repr.AST.ModuleRef, 1, sourceIndex)
repr.Meta.ResolvedExports[alias] = graph.ExportData{Ref: ref, SourceIndex: sourceIndex}
return prevExport{ref: ref, partIndex: partIndex}
}
// Unwrap JSON objects into separate top-level variables
var prevExports []js_ast.Ref
jsonValue := lazy.Value
if object, ok := jsonValue.Data.(*js_ast.EObject); ok {
clone := *object
clone.Properties = append(make([]js_ast.Property, 0, len(clone.Properties)), clone.Properties...)
for i, property := range clone.Properties {
if str, ok := property.Key.Data.(*js_ast.EString); ok &&
(!file.IsEntryPoint() || js_lexer.IsIdentifierUTF16(str.Value) ||
!c.options.UnsupportedJSFeatures.Has(compat.ArbitraryModuleNamespaceNames)) {
name := js_lexer.UTF16ToString(str.Value)
exportRef := generateExport(name, name, property.ValueOrNil).ref
prevExports = append(prevExports, exportRef)
clone.Properties[i].ValueOrNil = js_ast.Expr{Loc: property.Key.Loc, Data: &js_ast.EIdentifier{Ref: exportRef}}
}
}
jsonValue.Data = &clone
}
// Generate the default export
finalExportPartIndex := generateExport(file.InputFile.Source.IdentifierName+"_default", "default", jsonValue).partIndex
// The default export depends on all of the previous exports
for _, exportRef := range prevExports {
c.graph.GenerateSymbolImportAndUse(sourceIndex, finalExportPartIndex, exportRef, 1, sourceIndex)
}
}
func (c *linkerContext) createExportsForFile(sourceIndex uint32) {
////////////////////////////////////////////////////////////////////////////////
// WARNING: This method is run in parallel over all files. Do not mutate data
// for other files within this method or you will create a data race.
////////////////////////////////////////////////////////////////////////////////
file := &c.graph.Files[sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
// Generate a getter per export
properties := []js_ast.Property{}
nsExportDependencies := []js_ast.Dependency{}
nsExportSymbolUses := make(map[js_ast.Ref]js_ast.SymbolUse)
for _, alias := range repr.Meta.SortedAndFilteredExportAliases {
export := repr.Meta.ResolvedExports[alias]
// If this is an export of an import, reference the symbol that the import
// was eventually resolved to. We need to do this because imports have
// already been resolved by this point, so we can't generate a new import
// and have that be resolved later.
if importData, ok := c.graph.Files[export.SourceIndex].InputFile.Repr.(*graph.JSRepr).Meta.ImportsToBind[export.Ref]; ok {
export.Ref = importData.Ref
export.SourceIndex = importData.SourceIndex
nsExportDependencies = append(nsExportDependencies, importData.ReExports...)
}
// Exports of imports need EImportIdentifier in case they need to be re-
// written to a property access later on
var value js_ast.Expr
if c.graph.Symbols.Get(export.Ref).NamespaceAlias != nil {
value = js_ast.Expr{Data: &js_ast.EImportIdentifier{Ref: export.Ref}}
} else {
value = js_ast.Expr{Data: &js_ast.EIdentifier{Ref: export.Ref}}
}
// Add a getter property
var getter js_ast.Expr
body := js_ast.FnBody{Stmts: []js_ast.Stmt{{Loc: value.Loc, Data: &js_ast.SReturn{ValueOrNil: value}}}}
if c.options.UnsupportedJSFeatures.Has(compat.Arrow) {
getter = js_ast.Expr{Data: &js_ast.EFunction{Fn: js_ast.Fn{Body: body}}}
} else {
getter = js_ast.Expr{Data: &js_ast.EArrow{PreferExpr: true, Body: body}}
}
properties = append(properties, js_ast.Property{
Key: js_ast.Expr{Data: &js_ast.EString{Value: js_lexer.StringToUTF16(alias)}},
ValueOrNil: getter,
})
nsExportSymbolUses[export.Ref] = js_ast.SymbolUse{CountEstimate: 1}
// Make sure the part that declares the export is included
for _, partIndex := range c.graph.Files[export.SourceIndex].InputFile.Repr.(*graph.JSRepr).TopLevelSymbolToParts(export.Ref) {
// Use a non-local dependency since this is likely from a different
// file if it came in through an export star
nsExportDependencies = append(nsExportDependencies, js_ast.Dependency{
SourceIndex: export.SourceIndex,
PartIndex: partIndex,
})
}
}
declaredSymbols := []js_ast.DeclaredSymbol{}
var nsExportStmts []js_ast.Stmt
// Prefix this part with "var exports = {}" if this isn't a CommonJS entry point
if repr.Meta.NeedsExportsVariable {
nsExportStmts = append(nsExportStmts, js_ast.Stmt{Data: &js_ast.SLocal{Decls: []js_ast.Decl{{
Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: repr.AST.ExportsRef}},
ValueOrNil: js_ast.Expr{Data: &js_ast.EObject{}},
}}}})
declaredSymbols = append(declaredSymbols, js_ast.DeclaredSymbol{
Ref: repr.AST.ExportsRef,
IsTopLevel: true,
})
}
// "__export(exports, { foo: () => foo })"
exportRef := js_ast.InvalidRef
if len(properties) > 0 {
runtimeRepr := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr)
exportRef = runtimeRepr.AST.ModuleScope.Members["__export"].Ref
nsExportStmts = append(nsExportStmts, js_ast.Stmt{Data: &js_ast.SExpr{Value: js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: exportRef}},
Args: []js_ast.Expr{
{Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}},
{Data: &js_ast.EObject{
Properties: properties,
}},
},
}}}})
// Make sure this file depends on the "__export" symbol
for _, partIndex := range runtimeRepr.TopLevelSymbolToParts(exportRef) {
nsExportDependencies = append(nsExportDependencies, js_ast.Dependency{
SourceIndex: runtime.SourceIndex,
PartIndex: partIndex,
})
}
// Make sure the CommonJS closure, if there is one, includes "exports"
repr.AST.UsesExportsRef = true
}
// No need to generate a part if it'll be empty
if len(nsExportStmts) > 0 {
// Initialize the part that was allocated for us earlier. The information
// here will be used after this during tree shaking.
repr.AST.Parts[js_ast.NSExportPartIndex] = js_ast.Part{
Stmts: nsExportStmts,
SymbolUses: nsExportSymbolUses,
Dependencies: nsExportDependencies,
DeclaredSymbols: declaredSymbols,
// This can be removed if nothing uses it
CanBeRemovedIfUnused: true,
// Make sure this is trimmed if unused even if tree shaking is disabled
ForceTreeShaking: true,
}
// Pull in the "__export" symbol if it was used
if exportRef != js_ast.InvalidRef {
repr.Meta.NeedsExportSymbolFromRuntime = true
}
}
}
func (c *linkerContext) createWrapperForFile(sourceIndex uint32) {
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
switch repr.Meta.Wrap {
// If this is a CommonJS file, we're going to need to generate a wrapper
// for the CommonJS closure. That will end up looking something like this:
//
// var require_foo = __commonJS((exports, module) => {
// ...
// });
//
// However, that generation is special-cased for various reasons and is
// done later on. Still, we're going to need to ensure that this file
// both depends on the "__commonJS" symbol and declares the "require_foo"
// symbol. Instead of special-casing this during the reachablity analysis
// below, we just append a dummy part to the end of the file with these
// dependencies and let the general-purpose reachablity analysis take care
// of it.
case graph.WrapCJS:
runtimeRepr := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr)
commonJSParts := runtimeRepr.TopLevelSymbolToParts(c.cjsRuntimeRef)
// Generate the dummy part
dependencies := make([]js_ast.Dependency, len(commonJSParts))
for i, partIndex := range commonJSParts {
dependencies[i] = js_ast.Dependency{
SourceIndex: runtime.SourceIndex,
PartIndex: partIndex,
}
}
partIndex := c.graph.AddPartToFile(sourceIndex, js_ast.Part{
SymbolUses: map[js_ast.Ref]js_ast.SymbolUse{
repr.AST.WrapperRef: {CountEstimate: 1},
},
DeclaredSymbols: []js_ast.DeclaredSymbol{
{Ref: repr.AST.ExportsRef, IsTopLevel: true},
{Ref: repr.AST.ModuleRef, IsTopLevel: true},
{Ref: repr.AST.WrapperRef, IsTopLevel: true},
},
Dependencies: dependencies,
})
repr.Meta.WrapperPartIndex = ast.MakeIndex32(partIndex)
c.graph.GenerateSymbolImportAndUse(sourceIndex, partIndex, c.cjsRuntimeRef, 1, runtime.SourceIndex)
// If this is a lazily-initialized ESM file, we're going to need to
// generate a wrapper for the ESM closure. That will end up looking
// something like this:
//
// var init_foo = __esm(() => {
// ...
// });
//
// This depends on the "__esm" symbol and declares the "init_foo" symbol
// for similar reasons to the CommonJS closure above.
case graph.WrapESM:
runtimeRepr := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr)
esmParts := runtimeRepr.TopLevelSymbolToParts(c.esmRuntimeRef)
// Generate the dummy part
dependencies := make([]js_ast.Dependency, len(esmParts))
for i, partIndex := range esmParts {
dependencies[i] = js_ast.Dependency{
SourceIndex: runtime.SourceIndex,
PartIndex: partIndex,
}
}
partIndex := c.graph.AddPartToFile(sourceIndex, js_ast.Part{
SymbolUses: map[js_ast.Ref]js_ast.SymbolUse{
repr.AST.WrapperRef: {CountEstimate: 1},
},
DeclaredSymbols: []js_ast.DeclaredSymbol{
{Ref: repr.AST.WrapperRef, IsTopLevel: true},
},
Dependencies: dependencies,
})
repr.Meta.WrapperPartIndex = ast.MakeIndex32(partIndex)
c.graph.GenerateSymbolImportAndUse(sourceIndex, partIndex, c.esmRuntimeRef, 1, runtime.SourceIndex)
}
}
func (c *linkerContext) matchImportsWithExportsForFile(sourceIndex uint32) {
file := &c.graph.Files[sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
// Sort imports for determinism. Otherwise our unit tests will randomly
// fail sometimes when error messages are reordered.
sortedImportRefs := make([]int, 0, len(repr.AST.NamedImports))
for ref := range repr.AST.NamedImports {
sortedImportRefs = append(sortedImportRefs, int(ref.InnerIndex))
}
sort.Ints(sortedImportRefs)
// Pair imports with their matching exports
for _, innerIndex := range sortedImportRefs {
// Re-use memory for the cycle detector
c.cycleDetector = c.cycleDetector[:0]
importRef := js_ast.Ref{SourceIndex: sourceIndex, InnerIndex: uint32(innerIndex)}
result, reExports := c.matchImportWithExport(importTracker{sourceIndex: sourceIndex, importRef: importRef}, nil)
switch result.kind {
case matchImportIgnore:
case matchImportNormal:
repr.Meta.ImportsToBind[importRef] = graph.ImportData{
ReExports: reExports,
SourceIndex: result.sourceIndex,
Ref: result.ref,
}
case matchImportNamespace:
c.graph.Symbols.Get(importRef).NamespaceAlias = &js_ast.NamespaceAlias{
NamespaceRef: result.namespaceRef,
Alias: result.alias,
}
case matchImportNormalAndNamespace:
repr.Meta.ImportsToBind[importRef] = graph.ImportData{
ReExports: reExports,
SourceIndex: result.sourceIndex,
Ref: result.ref,
}
c.graph.Symbols.Get(importRef).NamespaceAlias = &js_ast.NamespaceAlias{
NamespaceRef: result.namespaceRef,
Alias: result.alias,
}
case matchImportCycle:
namedImport := repr.AST.NamedImports[importRef]
c.log.Add(logger.Error, file.LineColumnTracker(), js_lexer.RangeOfIdentifier(file.InputFile.Source, namedImport.AliasLoc),
fmt.Sprintf("Detected cycle while resolving import %q", namedImport.Alias))
case matchImportProbablyTypeScriptType:
repr.Meta.IsProbablyTypeScriptType[importRef] = true
case matchImportAmbiguous:
namedImport := repr.AST.NamedImports[importRef]
r := js_lexer.RangeOfIdentifier(file.InputFile.Source, namedImport.AliasLoc)
var notes []logger.MsgData
// Provide the locations of both ambiguous exports if possible
if result.nameLoc.Start != 0 && result.otherNameLoc.Start != 0 {
a := c.graph.Files[result.sourceIndex]
b := c.graph.Files[result.otherSourceIndex]
ra := js_lexer.RangeOfIdentifier(a.InputFile.Source, result.nameLoc)
rb := js_lexer.RangeOfIdentifier(b.InputFile.Source, result.otherNameLoc)
notes = []logger.MsgData{
a.LineColumnTracker().MsgData(ra, "One matching export is here:"),
b.LineColumnTracker().MsgData(rb, "Another matching export is here:"),
}
}
symbol := c.graph.Symbols.Get(importRef)
if symbol.ImportItemStatus == js_ast.ImportItemGenerated {
// This is a warning instead of an error because although it appears
// to be a named import, it's actually an automatically-generated
// named import that was originally a property access on an import
// star namespace object. Normally this property access would just
// resolve to undefined at run-time instead of failing at binding-
// time, so we emit a warning and rewrite the value to the literal
// "undefined" instead of emitting an error.
symbol.ImportItemStatus = js_ast.ImportItemMissing
msg := fmt.Sprintf("Import %q will always be undefined because there are multiple matching exports", namedImport.Alias)
c.log.AddWithNotes(logger.Warning, file.LineColumnTracker(), r, msg, notes)
} else {
msg := fmt.Sprintf("Ambiguous import %q has multiple matching exports", namedImport.Alias)
c.log.AddWithNotes(logger.Error, file.LineColumnTracker(), r, msg, notes)
}
}
}
}
type matchImportKind uint8
const (
// The import is either external or undefined
matchImportIgnore matchImportKind = iota
// "sourceIndex" and "ref" are in use
matchImportNormal
// "namespaceRef" and "alias" are in use
matchImportNamespace
// Both "matchImportNormal" and "matchImportNamespace"
matchImportNormalAndNamespace
// The import could not be evaluated due to a cycle
matchImportCycle
// The import is missing but came from a TypeScript file
matchImportProbablyTypeScriptType
// The import resolved to multiple symbols via "export * from"
matchImportAmbiguous
)
type matchImportResult struct {
kind matchImportKind
namespaceRef js_ast.Ref
alias string
sourceIndex uint32
nameLoc logger.Loc // Optional, goes with sourceIndex, ignore if zero
otherSourceIndex uint32
otherNameLoc logger.Loc // Optional, goes with otherSourceIndex, ignore if zero
ref js_ast.Ref
}
func (c *linkerContext) matchImportWithExport(
tracker importTracker, reExportsIn []js_ast.Dependency,
) (result matchImportResult, reExports []js_ast.Dependency) {
var ambiguousResults []matchImportResult
reExports = reExportsIn
loop:
for {
// Make sure we avoid infinite loops trying to resolve cycles:
//
// // foo.js
// export {a as b} from './foo.js'
// export {b as c} from './foo.js'
// export {c as a} from './foo.js'
//
// This uses a O(n^2) array scan instead of a O(n) map because the vast
// majority of cases have one or two elements and Go arrays are cheap to
// reuse without allocating.
for _, previousTracker := range c.cycleDetector {
if tracker == previousTracker {
result = matchImportResult{kind: matchImportCycle}
break loop
}
}
c.cycleDetector = append(c.cycleDetector, tracker)
// Resolve the import by one step
nextTracker, status, potentiallyAmbiguousExportStarRefs := c.advanceImportTracker(tracker)
switch status {
case importCommonJS, importCommonJSWithoutExports, importExternal, importDisabled:
if status == importExternal && c.options.OutputFormat.KeepES6ImportExportSyntax() {
// Imports from external modules should not be converted to CommonJS
// if the output format preserves the original ES6 import statements
break
}
// If it's a CommonJS or external file, rewrite the import to a
// property access. Don't do this if the namespace reference is invalid
// though. This is the case for star imports, where the import is the
// namespace.
trackerFile := &c.graph.Files[tracker.sourceIndex]
namedImport := trackerFile.InputFile.Repr.(*graph.JSRepr).AST.NamedImports[tracker.importRef]
if namedImport.NamespaceRef != js_ast.InvalidRef {
if result.kind == matchImportNormal {
result.kind = matchImportNormalAndNamespace
result.namespaceRef = namedImport.NamespaceRef
result.alias = namedImport.Alias
} else {
result = matchImportResult{
kind: matchImportNamespace,
namespaceRef: namedImport.NamespaceRef,
alias: namedImport.Alias,
}
}
}
// Warn about importing from a file that is known to not have any exports
if status == importCommonJSWithoutExports {
symbol := c.graph.Symbols.Get(tracker.importRef)
symbol.ImportItemStatus = js_ast.ImportItemMissing
c.log.Add(logger.Warning,
trackerFile.LineColumnTracker(),
js_lexer.RangeOfIdentifier(trackerFile.InputFile.Source, namedImport.AliasLoc),
fmt.Sprintf("Import %q will always be undefined because the file %q has no exports",
namedImport.Alias, c.graph.Files[nextTracker.sourceIndex].InputFile.Source.PrettyPath))
}
case importDynamicFallback:
// If it's a file with dynamic export fallback, rewrite the import to a property access
trackerFile := &c.graph.Files[tracker.sourceIndex]
namedImport := trackerFile.InputFile.Repr.(*graph.JSRepr).AST.NamedImports[tracker.importRef]
if result.kind == matchImportNormal {
result.kind = matchImportNormalAndNamespace
result.namespaceRef = nextTracker.importRef
result.alias = namedImport.Alias
} else {
result = matchImportResult{
kind: matchImportNamespace,
namespaceRef: nextTracker.importRef,
alias: namedImport.Alias,
}
}
case importNoMatch:
symbol := c.graph.Symbols.Get(tracker.importRef)
trackerFile := &c.graph.Files[tracker.sourceIndex]
namedImport := trackerFile.InputFile.Repr.(*graph.JSRepr).AST.NamedImports[tracker.importRef]
r := js_lexer.RangeOfIdentifier(trackerFile.InputFile.Source, namedImport.AliasLoc)
// Report mismatched imports and exports
if symbol.ImportItemStatus == js_ast.ImportItemGenerated {
// This is a warning instead of an error because although it appears
// to be a named import, it's actually an automatically-generated
// named import that was originally a property access on an import
// star namespace object. Normally this property access would just
// resolve to undefined at run-time instead of failing at binding-
// time, so we emit a warning and rewrite the value to the literal
// "undefined" instead of emitting an error.
symbol.ImportItemStatus = js_ast.ImportItemMissing
c.log.Add(logger.Warning, trackerFile.LineColumnTracker(), r, fmt.Sprintf(
"Import %q will always be undefined because there is no matching export in %q",
namedImport.Alias, c.graph.Files[nextTracker.sourceIndex].InputFile.Source.PrettyPath))
} else {
c.log.Add(logger.Error, trackerFile.LineColumnTracker(), r, fmt.Sprintf("No matching export in %q for import %q",
c.graph.Files[nextTracker.sourceIndex].InputFile.Source.PrettyPath, namedImport.Alias))
}
case importProbablyTypeScriptType:
// Omit this import from any namespace export code we generate for
// import star statements (i.e. "import * as ns from 'path'")
result = matchImportResult{kind: matchImportProbablyTypeScriptType}
case importFound:
// If there are multiple ambiguous results due to use of "export * from"
// statements, trace them all to see if they point to different things.
for _, ambiguousTracker := range potentiallyAmbiguousExportStarRefs {
// If this is a re-export of another import, follow the import
if _, ok := c.graph.Files[ambiguousTracker.SourceIndex].InputFile.Repr.(*graph.JSRepr).AST.NamedImports[ambiguousTracker.Ref]; ok {
// Save and restore the cycle detector to avoid mixing information
oldCycleDetector := c.cycleDetector
ambiguousResult, newReExportFiles := c.matchImportWithExport(importTracker{
sourceIndex: ambiguousTracker.SourceIndex,
importRef: ambiguousTracker.Ref,
}, reExports)
c.cycleDetector = oldCycleDetector
ambiguousResults = append(ambiguousResults, ambiguousResult)
reExports = newReExportFiles
} else {
ambiguousResults = append(ambiguousResults, matchImportResult{
kind: matchImportNormal,
sourceIndex: ambiguousTracker.SourceIndex,
ref: ambiguousTracker.Ref,
nameLoc: ambiguousTracker.NameLoc,
})
}
}
// Defer the actual binding of this import until after we generate
// namespace export code for all files. This has to be done for all
// import-to-export matches, not just the initial import to the final
// export, since all imports and re-exports must be merged together
// for correctness.
result = matchImportResult{
kind: matchImportNormal,
sourceIndex: nextTracker.sourceIndex,
ref: nextTracker.importRef,
nameLoc: nextTracker.nameLoc,
}
// Depend on the statement(s) that declared this import symbol in the
// original file
for _, resolvedPartIndex := range c.graph.Files[tracker.sourceIndex].InputFile.Repr.(*graph.JSRepr).TopLevelSymbolToParts(tracker.importRef) {
reExports = append(reExports, js_ast.Dependency{
SourceIndex: tracker.sourceIndex,
PartIndex: resolvedPartIndex,
})
}
// If this is a re-export of another import, continue for another
// iteration of the loop to resolve that import as well
if _, ok := c.graph.Files[nextTracker.sourceIndex].InputFile.Repr.(*graph.JSRepr).AST.NamedImports[nextTracker.importRef]; ok {
tracker = nextTracker
continue
}
default:
panic("Internal error")
}
// Stop now if we didn't explicitly "continue" above
break
}
// If there is a potential ambiguity, all results must be the same
for _, ambiguousResult := range ambiguousResults {
if ambiguousResult != result {
if result.kind == matchImportNormal && ambiguousResult.kind == matchImportNormal &&
result.nameLoc.Start != 0 && ambiguousResult.nameLoc.Start != 0 {
return matchImportResult{
kind: matchImportAmbiguous,
sourceIndex: result.sourceIndex,
nameLoc: result.nameLoc,
otherSourceIndex: ambiguousResult.sourceIndex,
otherNameLoc: ambiguousResult.nameLoc,
}, nil
}
return matchImportResult{kind: matchImportAmbiguous}, nil
}
}
return
}
func (c *linkerContext) recursivelyWrapDependencies(sourceIndex uint32) {
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
if repr.Meta.DidWrapDependencies {
return
}
repr.Meta.DidWrapDependencies = true
// Never wrap the runtime file since it always comes first
if sourceIndex == runtime.SourceIndex {
return
}
// This module must be wrapped
if repr.Meta.Wrap == graph.WrapNone {
if repr.AST.ExportsKind == js_ast.ExportsCommonJS {
repr.Meta.Wrap = graph.WrapCJS
} else {
repr.Meta.Wrap = graph.WrapESM
}
}
// All dependencies must also be wrapped
for _, record := range repr.AST.ImportRecords {
if record.SourceIndex.IsValid() {
c.recursivelyWrapDependencies(record.SourceIndex.GetIndex())
}
}
}
func (c *linkerContext) hasDynamicExportsDueToExportStar(sourceIndex uint32, visited map[uint32]bool) bool {
// Terminate the traversal now if this file already has dynamic exports
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
if repr.AST.ExportsKind == js_ast.ExportsCommonJS || repr.AST.ExportsKind == js_ast.ExportsESMWithDynamicFallback {
return true
}
// Avoid infinite loops due to cycles in the export star graph
if visited[sourceIndex] {
return false
}
visited[sourceIndex] = true
// Scan over the export star graph
for _, importRecordIndex := range repr.AST.ExportStarImportRecords {
record := &repr.AST.ImportRecords[importRecordIndex]
// This file has dynamic exports if the exported imports are from a file
// that either has dynamic exports directly or transitively by itself
// having an export star from a file with dynamic exports.
if (!record.SourceIndex.IsValid() && (!c.graph.Files[sourceIndex].IsEntryPoint() || !c.options.OutputFormat.KeepES6ImportExportSyntax())) ||
(record.SourceIndex.IsValid() && record.SourceIndex.GetIndex() != sourceIndex && c.hasDynamicExportsDueToExportStar(record.SourceIndex.GetIndex(), visited)) {
repr.AST.ExportsKind = js_ast.ExportsESMWithDynamicFallback
return true
}
}
return false
}
func (c *linkerContext) addExportsForExportStar(
resolvedExports map[string]graph.ExportData,
sourceIndex uint32,
sourceIndexStack []uint32,
) {
// Avoid infinite loops due to cycles in the export star graph
for _, prevSourceIndex := range sourceIndexStack {
if prevSourceIndex == sourceIndex {
return
}
}
sourceIndexStack = append(sourceIndexStack, sourceIndex)
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
for _, importRecordIndex := range repr.AST.ExportStarImportRecords {
record := &repr.AST.ImportRecords[importRecordIndex]
if !record.SourceIndex.IsValid() {
// This will be resolved at run time instead
continue
}
otherSourceIndex := record.SourceIndex.GetIndex()
// Export stars from a CommonJS module don't work because they can't be
// statically discovered. Just silently ignore them in this case.
//
// We could attempt to check whether the imported file still has ES6
// exports even though it still uses CommonJS features. However, when
// doing this we'd also have to rewrite any imports of these export star
// re-exports as property accesses off of a generated require() call.
otherRepr := c.graph.Files[otherSourceIndex].InputFile.Repr.(*graph.JSRepr)
if otherRepr.AST.ExportsKind == js_ast.ExportsCommonJS {
// All exports will be resolved at run time instead
continue
}
// Accumulate this file's exports
nextExport:
for alias, name := range otherRepr.AST.NamedExports {
// ES6 export star statements ignore exports named "default"
if alias == "default" {
continue
}
// This export star is shadowed if any file in the stack has a matching real named export
for _, prevSourceIndex := range sourceIndexStack {
prevRepr := c.graph.Files[prevSourceIndex].InputFile.Repr.(*graph.JSRepr)
if _, ok := prevRepr.AST.NamedExports[alias]; ok {
continue nextExport
}
}
if existing, ok := resolvedExports[alias]; !ok {
// Initialize the re-export
resolvedExports[alias] = graph.ExportData{
Ref: name.Ref,
SourceIndex: otherSourceIndex,
NameLoc: name.AliasLoc,
}
// Make sure the symbol is marked as imported so that code splitting
// imports it correctly if it ends up being shared with another chunk
repr.Meta.ImportsToBind[name.Ref] = graph.ImportData{
Ref: name.Ref,
SourceIndex: otherSourceIndex,
}
} else if existing.SourceIndex != otherSourceIndex {
// Two different re-exports colliding makes it potentially ambiguous
existing.PotentiallyAmbiguousExportStarRefs =
append(existing.PotentiallyAmbiguousExportStarRefs, graph.ImportData{
SourceIndex: otherSourceIndex,
Ref: name.Ref,
NameLoc: name.AliasLoc,
})
resolvedExports[alias] = existing
}
}
// Search further through this file's export stars
c.addExportsForExportStar(resolvedExports, otherSourceIndex, sourceIndexStack)
}
}
type importTracker struct {
sourceIndex uint32
nameLoc logger.Loc // Optional, goes with sourceIndex, ignore if zero
importRef js_ast.Ref
}
type importStatus uint8
const (
// The imported file has no matching export
importNoMatch importStatus = iota
// The imported file has a matching export
importFound
// The imported file is CommonJS and has unknown exports
importCommonJS
// The import is missing but there is a dynamic fallback object
importDynamicFallback
// The import was treated as a CommonJS import but the file is known to have no exports
importCommonJSWithoutExports
// The imported file was disabled by mapping it to false in the "browser"
// field of package.json
importDisabled
// The imported file is external and has unknown exports
importExternal
// This is a missing re-export in a TypeScript file, so it's probably a type
importProbablyTypeScriptType
)
func (c *linkerContext) advanceImportTracker(tracker importTracker) (importTracker, importStatus, []graph.ImportData) {
file := &c.graph.Files[tracker.sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
namedImport := repr.AST.NamedImports[tracker.importRef]
// Is this an external file?
record := &repr.AST.ImportRecords[namedImport.ImportRecordIndex]
if !record.SourceIndex.IsValid() {
return importTracker{}, importExternal, nil
}
// Is this a disabled file?
otherSourceIndex := record.SourceIndex.GetIndex()
if c.graph.Files[otherSourceIndex].InputFile.Source.KeyPath.IsDisabled() {
return importTracker{sourceIndex: otherSourceIndex, importRef: js_ast.InvalidRef}, importDisabled, nil
}
// Is this a named import of a file without any exports?
otherRepr := c.graph.Files[otherSourceIndex].InputFile.Repr.(*graph.JSRepr)
if !namedImport.AliasIsStar && !otherRepr.AST.HasLazyExport &&
// CommonJS exports
otherRepr.AST.ExportKeyword.Len == 0 && namedImport.Alias != "default" &&
// ESM exports
!otherRepr.AST.UsesExportsRef && !otherRepr.AST.UsesModuleRef {
// Just warn about it and replace the import with "undefined"
return importTracker{sourceIndex: otherSourceIndex, importRef: js_ast.InvalidRef}, importCommonJSWithoutExports, nil
}
// Is this a CommonJS file?
if otherRepr.AST.ExportsKind == js_ast.ExportsCommonJS {
return importTracker{sourceIndex: otherSourceIndex, importRef: js_ast.InvalidRef}, importCommonJS, nil
}
// Match this import star with an export star from the imported file
if matchingExport := otherRepr.Meta.ResolvedExportStar; namedImport.AliasIsStar && matchingExport != nil {
// Check to see if this is a re-export of another import
return importTracker{
sourceIndex: matchingExport.SourceIndex,
importRef: matchingExport.Ref,
nameLoc: matchingExport.NameLoc,
}, importFound, matchingExport.PotentiallyAmbiguousExportStarRefs
}
// Match this import up with an export from the imported file
if matchingExport, ok := otherRepr.Meta.ResolvedExports[namedImport.Alias]; ok {
// Check to see if this is a re-export of another import
return importTracker{
sourceIndex: matchingExport.SourceIndex,
importRef: matchingExport.Ref,
nameLoc: matchingExport.NameLoc,
}, importFound, matchingExport.PotentiallyAmbiguousExportStarRefs
}
// Is this a file with dynamic exports?
if otherRepr.AST.ExportsKind == js_ast.ExportsESMWithDynamicFallback {
return importTracker{sourceIndex: otherSourceIndex, importRef: otherRepr.AST.ExportsRef}, importDynamicFallback, nil
}
// Missing re-exports in TypeScript files are indistinguishable from types
if file.InputFile.Loader.IsTypeScript() && namedImport.IsExported {
return importTracker{}, importProbablyTypeScriptType, nil
}
return importTracker{sourceIndex: otherSourceIndex}, importNoMatch, nil
}
func (c *linkerContext) treeShakingAndCodeSplitting() {
// Tree shaking: Each entry point marks all files reachable from itself
c.timer.Begin("Tree shaking")
for _, entryPoint := range c.graph.EntryPoints() {
c.markFileLiveForTreeShaking(entryPoint.SourceIndex)
}
c.timer.End("Tree shaking")
// Code splitting: Determine which entry points can reach which files. This
// has to happen after tree shaking because there is an implicit dependency
// between live parts within the same file. All liveness has to be computed
// first before determining which entry points can reach which files.
c.timer.Begin("Code splitting")
for i, entryPoint := range c.graph.EntryPoints() {
c.markFileReachableForCodeSplitting(entryPoint.SourceIndex, uint(i), 0)
}
c.timer.End("Code splitting")
}
func (c *linkerContext) markFileReachableForCodeSplitting(sourceIndex uint32, entryPointBit uint, distanceFromEntryPoint uint32) {
file := &c.graph.Files[sourceIndex]
if !file.IsLive {
return
}
traverseAgain := false
// Track the minimum distance to an entry point
if distanceFromEntryPoint < file.DistanceFromEntryPoint {
file.DistanceFromEntryPoint = distanceFromEntryPoint
traverseAgain = true
}
distanceFromEntryPoint++
// Don't mark this file more than once
if file.EntryBits.HasBit(entryPointBit) && !traverseAgain {
return
}
file.EntryBits.SetBit(entryPointBit)
switch repr := file.InputFile.Repr.(type) {
case *graph.JSRepr:
// If the JavaScript stub for a CSS file is included, also include the CSS file
if repr.CSSSourceIndex.IsValid() {
c.markFileReachableForCodeSplitting(repr.CSSSourceIndex.GetIndex(), entryPointBit, distanceFromEntryPoint)
}
// Traverse into all imported files
for _, record := range repr.AST.ImportRecords {
if record.SourceIndex.IsValid() && !c.isExternalDynamicImport(&record, sourceIndex) {
c.markFileReachableForCodeSplitting(record.SourceIndex.GetIndex(), entryPointBit, distanceFromEntryPoint)
}
}
// Traverse into all dependencies of all parts in this file
for _, part := range repr.AST.Parts {
for _, dependency := range part.Dependencies {
if dependency.SourceIndex != sourceIndex {
c.markFileReachableForCodeSplitting(dependency.SourceIndex, entryPointBit, distanceFromEntryPoint)
}
}
}
case *graph.CSSRepr:
// Traverse into all dependencies
for _, record := range repr.AST.ImportRecords {
if record.SourceIndex.IsValid() {
c.markFileReachableForCodeSplitting(record.SourceIndex.GetIndex(), entryPointBit, distanceFromEntryPoint)
}
}
}
}
func (c *linkerContext) markFileLiveForTreeShaking(sourceIndex uint32) {
file := &c.graph.Files[sourceIndex]
// Don't mark this file more than once
if file.IsLive {
return
}
file.IsLive = true
switch repr := file.InputFile.Repr.(type) {
case *graph.JSRepr:
// If the JavaScript stub for a CSS file is included, also include the CSS file
if repr.CSSSourceIndex.IsValid() {
c.markFileLiveForTreeShaking(repr.CSSSourceIndex.GetIndex())
}
for partIndex, part := range repr.AST.Parts {
canBeRemovedIfUnused := part.CanBeRemovedIfUnused
// Also include any statement-level imports
for _, importRecordIndex := range part.ImportRecordIndices {
record := &repr.AST.ImportRecords[importRecordIndex]
if record.Kind != ast.ImportStmt {
continue
}
if record.SourceIndex.IsValid() {
otherSourceIndex := record.SourceIndex.GetIndex()
// Don't include this module for its side effects if it can be
// considered to have no side effects
if otherFile := &c.graph.Files[otherSourceIndex]; otherFile.InputFile.SideEffects.Kind != graph.HasSideEffects && !c.options.IgnoreDCEAnnotations {
continue
}
// Otherwise, include this module for its side effects
c.markFileLiveForTreeShaking(otherSourceIndex)
}
// If we get here then the import was included for its side effects, so
// we must also keep this part
canBeRemovedIfUnused = false
}
// Include all parts in this file with side effects, or just include
// everything if tree-shaking is disabled. Note that we still want to
// perform tree-shaking on the runtime even if tree-shaking is disabled.
if !canBeRemovedIfUnused || (!part.ForceTreeShaking && !c.options.TreeShaking && file.IsEntryPoint()) {
c.markPartLiveForTreeShaking(sourceIndex, uint32(partIndex))
}
}
case *graph.CSSRepr:
// Include all "@import" rules
for _, record := range repr.AST.ImportRecords {
if record.SourceIndex.IsValid() {
c.markFileLiveForTreeShaking(record.SourceIndex.GetIndex())
}
}
}
}
func (c *linkerContext) isExternalDynamicImport(record *ast.ImportRecord, sourceIndex uint32) bool {
return record.Kind == ast.ImportDynamic && c.graph.Files[record.SourceIndex.GetIndex()].IsEntryPoint() && record.SourceIndex.GetIndex() != sourceIndex
}
func (c *linkerContext) markPartLiveForTreeShaking(sourceIndex uint32, partIndex uint32) {
file := &c.graph.Files[sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
part := &repr.AST.Parts[partIndex]
// Don't mark this part more than once
if part.IsLive {
return
}
part.IsLive = true
// Include the file containing this part
c.markFileLiveForTreeShaking(sourceIndex)
// Also include any dependencies
for _, dep := range part.Dependencies {
c.markPartLiveForTreeShaking(dep.SourceIndex, dep.PartIndex)
}
}
func sanitizeFilePathForVirtualModulePath(path string) string {
// Convert it to a safe file path. See: https://stackoverflow.com/a/31976060
sb := strings.Builder{}
needsGap := false
for _, c := range path {
switch c {
case 0:
// These characters are forbidden on Unix and Windows
case '<', '>', ':', '"', '|', '?', '*':
// These characters are forbidden on Windows
default:
if c < 0x20 {
// These characters are forbidden on Windows
break
}
// Turn runs of invalid characters into a '_'
if needsGap {
sb.WriteByte('_')
needsGap = false
}
sb.WriteRune(c)
continue
}
if sb.Len() > 0 {
needsGap = true
}
}
// Make sure the name isn't empty
if sb.Len() == 0 {
return "_"
}
// Note: An extension will be added to this base name, so there is no need to
// avoid forbidden file names such as ".." since ".js" is a valid file name.
return sb.String()
}
// JavaScript modules are traversed in depth-first postorder. This is the
// order that JavaScript modules were evaluated in before the top-level await
// feature was introduced.
//
// A
// / \
// B C
// \ /
// D
//
// If A imports B and then C, B imports D, and C imports D, then the JavaScript
// traversal order is D B C A.
//
// This function may deviate from ESM import order for dynamic imports (both
// "require()" and "import()"). This is because the import order is impossible
// to determine since the imports happen at run-time instead of compile-time.
// In this case we just pick an arbitrary but consistent order.
func (c *linkerContext) findImportedCSSFilesInJSOrder(entryPoint uint32) (order []uint32) {
visited := make(map[uint32]bool)
var visit func(uint32, ast.Index32)
// Include this file and all files it imports
visit = func(sourceIndex uint32, importerIndex ast.Index32) {
if visited[sourceIndex] {
return
}
visited[sourceIndex] = true
file := &c.graph.Files[sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
// Iterate over each part in the file in order
for _, part := range repr.AST.Parts {
// Ignore dead code that has been removed from the bundle. Any code
// that's reachable from the entry point, even through lazy dynamic
// imports, could end up being activated by the bundle and needs its
// CSS to be included. This may change if/when code splitting is
// supported for CSS.
if !part.IsLive {
continue
}
// Traverse any files imported by this part. Note that CommonJS calls
// to "require()" count as imports too, sort of as if the part has an
// ESM "import" statement in it. This may seem weird because ESM imports
// are a compile-time concept while CommonJS imports are a run-time
// concept. But we don't want to manipulate <style> tags at run-time so
// this is the only way to do it.
for _, importRecordIndex := range part.ImportRecordIndices {
if record := &repr.AST.ImportRecords[importRecordIndex]; record.SourceIndex.IsValid() {
visit(record.SourceIndex.GetIndex(), ast.MakeIndex32(sourceIndex))
}
}
}
// Iterate over the associated CSS imports in postorder
if repr.CSSSourceIndex.IsValid() {
order = append(order, repr.CSSSourceIndex.GetIndex())
}
}
// Include all files reachable from the entry point
visit(entryPoint, ast.Index32{})
return
}
// CSS files are traversed in depth-first reversed reverse preorder. This is
// because unlike JavaScript import statements, CSS "@import" rules are
// evaluated every time instead of just the first time. However, evaluating a
// CSS file multiple times is equivalent to evaluating it once at the last
// location. So we drop all but the last evaluation in the order.
//
// A
// / \
// B C
// \ /
// D
//
// If A imports B and then C, B imports D, and C imports D, then the CSS
// traversal order is B D C A.
func (c *linkerContext) findImportedFilesInCSSOrder(entryPoints []uint32) (externalOrder []externalImportCSS, internalOrder []uint32) {
type externalImportsCSS struct {
unconditional bool
conditions [][]css_ast.Token
}
visited := make(map[uint32]bool)
externals := make(map[logger.Path]externalImportsCSS)
var visit func(uint32, ast.Index32)
// Include this file and all files it imports
visit = func(sourceIndex uint32, importerIndex ast.Index32) {
if !visited[sourceIndex] {
visited[sourceIndex] = true
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.CSSRepr)
topLevelRules := repr.AST.Rules
// Iterate in reverse preorder (will be reversed again later)
internalOrder = append(internalOrder, sourceIndex)
// Iterate in the inverse order of top-level "@import" rules
outer:
for i := len(topLevelRules) - 1; i >= 0; i-- {
if atImport, ok := topLevelRules[i].Data.(*css_ast.RAtImport); ok {
if record := &repr.AST.ImportRecords[atImport.ImportRecordIndex]; record.SourceIndex.IsValid() {
// Follow internal dependencies
visit(record.SourceIndex.GetIndex(), ast.MakeIndex32(sourceIndex))
} else {
// Record external dependencies
external := externals[record.Path]
// Check for an unconditional import. An unconditional import
// should always mask all conditional imports that are overridden
// by the unconditional import.
if external.unconditional {
continue
}
if len(atImport.ImportConditions) == 0 {
external.unconditional = true
} else {
// Check for a conditional import. A conditional import does not
// mask an earlier unconditional import because re-evaluating a
// CSS file can have observable results.
for _, tokens := range external.conditions {
if css_ast.TokensEqualIgnoringWhitespace(tokens, atImport.ImportConditions) {
continue outer
}
}
external.conditions = append(external.conditions, atImport.ImportConditions)
}
// Clone any import records associated with the condition tokens
conditions, conditionImportRecords := css_ast.CloneTokensWithImportRecords(
atImport.ImportConditions, repr.AST.ImportRecords, nil, nil)
externals[record.Path] = external
externalOrder = append(externalOrder, externalImportCSS{
path: record.Path,
conditions: conditions,
conditionImportRecords: conditionImportRecords,
})
}
}
}
}
}
// Include all files reachable from any entry point
for i := len(entryPoints) - 1; i >= 0; i-- {
visit(entryPoints[i], ast.Index32{})
}
// Reverse the order afterward when traversing in CSS order
for i, j := 0, len(internalOrder)-1; i < j; i, j = i+1, j-1 {
internalOrder[i], internalOrder[j] = internalOrder[j], internalOrder[i]
}
for i, j := 0, len(externalOrder)-1; i < j; i, j = i+1, j-1 {
externalOrder[i], externalOrder[j] = externalOrder[j], externalOrder[i]
}
return
}
func (c *linkerContext) computeChunks() []chunkInfo {
c.timer.Begin("Compute chunks")
defer c.timer.End("Compute chunks")
jsChunks := make(map[string]chunkInfo)
cssChunks := make(map[string]chunkInfo)
// Create chunks for entry points
for i, entryPoint := range c.graph.EntryPoints() {
file := &c.graph.Files[entryPoint.SourceIndex]
// Create a chunk for the entry point here to ensure that the chunk is
// always generated even if the resulting file is empty
entryBits := helpers.NewBitSet(uint(len(c.graph.EntryPoints())))
entryBits.SetBit(uint(i))
key := entryBits.String()
chunk := chunkInfo{
entryBits: entryBits,
isEntryPoint: true,
sourceIndex: entryPoint.SourceIndex,
entryPointBit: uint(i),
filesWithPartsInChunk: make(map[uint32]bool),
}
switch file.InputFile.Repr.(type) {
case *graph.JSRepr:
chunk.chunkRepr = &chunkReprJS{}
jsChunks[key] = chunk
// If this JS entry point has an associated CSS entry point, generate it
// now. This is essentially done by generating a virtual CSS file that
// only contains "@import" statements in the order that the files were
// discovered in JS source order, where JS source order is arbitrary but
// consistent for dynamic imports. Then we run the CSS import order
// algorithm to determine the final CSS file order for the chunk.
if cssSourceIndices := c.findImportedCSSFilesInJSOrder(entryPoint.SourceIndex); len(cssSourceIndices) > 0 {
externalOrder, internalOrder := c.findImportedFilesInCSSOrder(cssSourceIndices)
cssFilesWithPartsInChunk := make(map[uint32]bool)
for _, sourceIndex := range internalOrder {
cssFilesWithPartsInChunk[uint32(sourceIndex)] = true
}
cssChunks[key] = chunkInfo{
entryBits: entryBits,
isEntryPoint: true,
sourceIndex: entryPoint.SourceIndex,
entryPointBit: uint(i),
filesWithPartsInChunk: cssFilesWithPartsInChunk,
chunkRepr: &chunkReprCSS{
externalImportsInOrder: externalOrder,
filesInChunkInOrder: internalOrder,
},
}
}
case *graph.CSSRepr:
externalOrder, internalOrder := c.findImportedFilesInCSSOrder([]uint32{entryPoint.SourceIndex})
for _, sourceIndex := range internalOrder {
chunk.filesWithPartsInChunk[uint32(sourceIndex)] = true
}
chunk.chunkRepr = &chunkReprCSS{
externalImportsInOrder: externalOrder,
filesInChunkInOrder: internalOrder,
}
cssChunks[key] = chunk
}
}
// Figure out which JS files are in which chunk
for _, sourceIndex := range c.graph.ReachableFiles {
if file := &c.graph.Files[sourceIndex]; file.IsLive {
if _, ok := file.InputFile.Repr.(*graph.JSRepr); ok {
key := file.EntryBits.String()
chunk, ok := jsChunks[key]
if !ok {
chunk.entryBits = file.EntryBits
chunk.filesWithPartsInChunk = make(map[uint32]bool)
chunk.chunkRepr = &chunkReprJS{}
jsChunks[key] = chunk
}
chunk.filesWithPartsInChunk[uint32(sourceIndex)] = true
}
}
}
// Sort the chunks for determinism. This matters because we use chunk indices
// as sorting keys in a few places.
sortedChunks := make([]chunkInfo, 0, len(jsChunks)+len(cssChunks))
sortedKeys := make([]string, 0, len(jsChunks)+len(cssChunks))
for key := range jsChunks {
sortedKeys = append(sortedKeys, key)
}
sort.Strings(sortedKeys)
for _, key := range sortedKeys {
sortedChunks = append(sortedChunks, jsChunks[key])
}
sortedKeys = sortedKeys[:0]
for key := range cssChunks {
sortedKeys = append(sortedKeys, key)
}
sort.Strings(sortedKeys)
for _, key := range sortedKeys {
sortedChunks = append(sortedChunks, cssChunks[key])
}
// Map from the entry point file to this chunk. We will need this later if
// a file contains a dynamic import to this entry point, since we'll need
// to look up the path for this chunk to use with the import.
for chunkIndex, chunk := range sortedChunks {
if chunk.isEntryPoint {
file := &c.graph.Files[chunk.sourceIndex]
// JS entry points that import CSS files generate two chunks, a JS chunk
// and a CSS chunk. Don't link the CSS chunk to the JS file since the CSS
// chunk is secondary (the JS chunk is primary).
if _, ok := chunk.chunkRepr.(*chunkReprCSS); ok {
if _, ok := file.InputFile.Repr.(*graph.JSRepr); ok {
continue
}
}
file.EntryPointChunkIndex = uint32(chunkIndex)
}
}
// Determine the order of JS files (and parts) within the chunk ahead of time
for _, chunk := range sortedChunks {
if chunkRepr, ok := chunk.chunkRepr.(*chunkReprJS); ok {
chunkRepr.filesInChunkInOrder, chunkRepr.partsInChunkInOrder = c.findImportedPartsInJSOrder(&chunk)
}
}
// Assign general information to each chunk
for chunkIndex := range sortedChunks {
chunk := &sortedChunks[chunkIndex]
// Assign a unique key to each chunk. This key encodes the index directly so
// we can easily recover it later without needing to look it up in a map. The
// last 8 numbers of the key are the chunk index.
chunk.uniqueKey = fmt.Sprintf("%sC%08d", c.uniqueKeyPrefix, chunkIndex)
// Determine the standard file extension
var stdExt string
switch chunk.chunkRepr.(type) {
case *chunkReprJS:
stdExt = c.options.OutputExtensionJS
case *chunkReprCSS:
stdExt = c.options.OutputExtensionCSS
}
// Compute the template substitutions
var dir, base, ext string
var template []config.PathTemplate
if chunk.isEntryPoint {
// Only use the entry path template for user-specified entry points
file := &c.graph.Files[chunk.sourceIndex]
if file.IsUserSpecifiedEntryPoint() {
template = c.options.EntryPathTemplate
} else {
template = c.options.ChunkPathTemplate
}
if c.options.AbsOutputFile != "" {
// If the output path was configured explicitly, use it verbatim
dir = "/"
base = c.fs.Base(c.options.AbsOutputFile)
originalExt := c.fs.Ext(base)
base = base[:len(base)-len(originalExt)]
// Use the extension from the explicit output file path. However, don't do
// that if this is a CSS chunk but the entry point file is not CSS. In that
// case use the standard extension. This happens when importing CSS into JS.
if _, ok := file.InputFile.Repr.(*graph.CSSRepr); ok || stdExt != c.options.OutputExtensionCSS {
ext = originalExt
} else {
ext = stdExt
}
} else {
// Otherwise, derive the output path from the input path
dir, base = pathRelativeToOutbase(
&c.graph.Files[chunk.sourceIndex].InputFile,
c.options,
c.fs,
!file.IsUserSpecifiedEntryPoint(),
c.graph.EntryPoints()[chunk.entryPointBit].OutputPath,
)
ext = stdExt
}
} else {
dir = "/"
base = "chunk"
ext = stdExt
template = c.options.ChunkPathTemplate
}
// Determine the output path template
templateExt := strings.TrimPrefix(ext, ".")
template = append(append(make([]config.PathTemplate, 0, len(template)+1), template...), config.PathTemplate{Data: ext})
chunk.finalTemplate = config.SubstituteTemplate(template, config.PathPlaceholders{
Dir: &dir,
Name: &base,
Ext: &templateExt,
})
}
return sortedChunks
}
type chunkOrder struct {
sourceIndex uint32
distance uint32
tieBreaker uint32
}
// This type is just so we can use Go's native sort function
type chunkOrderArray []chunkOrder
func (a chunkOrderArray) Len() int { return len(a) }
func (a chunkOrderArray) Swap(i int, j int) { a[i], a[j] = a[j], a[i] }
func (a chunkOrderArray) Less(i int, j int) bool {
ai := a[i]
aj := a[j]
return ai.distance < aj.distance || (ai.distance == aj.distance && ai.tieBreaker < aj.tieBreaker)
}
func appendOrExtendPartRange(ranges []partRange, sourceIndex uint32, partIndex uint32) []partRange {
if i := len(ranges) - 1; i >= 0 {
if r := &ranges[i]; r.sourceIndex == sourceIndex && r.partIndexEnd == partIndex {
r.partIndexEnd = partIndex + 1
return ranges
}
}
return append(ranges, partRange{
sourceIndex: sourceIndex,
partIndexBegin: partIndex,
partIndexEnd: partIndex + 1,
})
}
func (c *linkerContext) shouldIncludePart(repr *graph.JSRepr, part js_ast.Part) bool {
// As an optimization, ignore parts containing a single import statement to
// an internal non-wrapped file. These will be ignored anyway and it's a
// performance hit to spin up a goroutine only to discover this later.
if len(part.Stmts) == 1 {
if s, ok := part.Stmts[0].Data.(*js_ast.SImport); ok {
record := &repr.AST.ImportRecords[s.ImportRecordIndex]
if record.SourceIndex.IsValid() && c.graph.Files[record.SourceIndex.GetIndex()].InputFile.Repr.(*graph.JSRepr).Meta.Wrap == graph.WrapNone {
return false
}
}
}
return true
}
func (c *linkerContext) findImportedPartsInJSOrder(chunk *chunkInfo) (js []uint32, jsParts []partRange) {
sorted := make(chunkOrderArray, 0, len(chunk.filesWithPartsInChunk))
// Attach information to the files for use with sorting
for sourceIndex := range chunk.filesWithPartsInChunk {
file := &c.graph.Files[sourceIndex]
sorted = append(sorted, chunkOrder{
sourceIndex: sourceIndex,
distance: file.DistanceFromEntryPoint,
tieBreaker: c.graph.StableSourceIndices[sourceIndex],
})
}
// Sort so files closest to an entry point come first. If two files are
// equidistant to an entry point, then break the tie by sorting on the
// stable source index derived from the DFS over all entry points.
sort.Sort(sorted)
visited := make(map[uint32]bool)
jsPartsPrefix := []partRange{}
// Traverse the graph using this stable order and linearize the files with
// dependencies before dependents
var visit func(uint32)
visit = func(sourceIndex uint32) {
if visited[sourceIndex] {
return
}
visited[sourceIndex] = true
file := &c.graph.Files[sourceIndex]
if repr, ok := file.InputFile.Repr.(*graph.JSRepr); ok {
isFileInThisChunk := chunk.entryBits.Equals(file.EntryBits)
// Wrapped files can't be split because they are all inside the wrapper
canFileBeSplit := repr.Meta.Wrap == graph.WrapNone
// Make sure the generated call to "__export(exports, ...)" comes first
// before anything else in this file
if canFileBeSplit && isFileInThisChunk && repr.AST.Parts[js_ast.NSExportPartIndex].IsLive {
jsParts = appendOrExtendPartRange(jsParts, sourceIndex, js_ast.NSExportPartIndex)
}
for partIndex, part := range repr.AST.Parts {
isPartInThisChunk := isFileInThisChunk && repr.AST.Parts[partIndex].IsLive
// Also traverse any files imported by this part
for _, importRecordIndex := range part.ImportRecordIndices {
record := &repr.AST.ImportRecords[importRecordIndex]
if record.SourceIndex.IsValid() && (record.Kind == ast.ImportStmt || isPartInThisChunk) {
if c.isExternalDynamicImport(record, sourceIndex) {
// Don't follow import() dependencies
continue
}
visit(record.SourceIndex.GetIndex())
}
}
// Then include this part after the files it imports
if isPartInThisChunk {
isFileInThisChunk = true
if canFileBeSplit && uint32(partIndex) != js_ast.NSExportPartIndex && c.shouldIncludePart(repr, part) {
if sourceIndex == runtime.SourceIndex {
jsPartsPrefix = appendOrExtendPartRange(jsPartsPrefix, sourceIndex, uint32(partIndex))
} else {
jsParts = appendOrExtendPartRange(jsParts, sourceIndex, uint32(partIndex))
}
}
}
}
if isFileInThisChunk {
js = append(js, sourceIndex)
// CommonJS files are all-or-nothing so all parts must be contiguous
if !canFileBeSplit {
jsPartsPrefix = append(jsPartsPrefix, partRange{
sourceIndex: sourceIndex,
partIndexBegin: 0,
partIndexEnd: uint32(len(repr.AST.Parts)),
})
}
}
}
}
// Always put the runtime code first before anything else
visit(runtime.SourceIndex)
for _, data := range sorted {
visit(data.sourceIndex)
}
jsParts = append(jsPartsPrefix, jsParts...)
return
}
func (c *linkerContext) shouldRemoveImportExportStmt(
sourceIndex uint32,
stmtList *stmtList,
loc logger.Loc,
namespaceRef js_ast.Ref,
importRecordIndex uint32,
) bool {
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
record := &repr.AST.ImportRecords[importRecordIndex]
// Is this an external import?
if !record.SourceIndex.IsValid() {
// Keep the "import" statement if "import" statements are supported
if c.options.OutputFormat.KeepES6ImportExportSyntax() {
return false
}
// Otherwise, replace this statement with a call to "require()"
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{
Loc: loc,
Data: &js_ast.SLocal{Decls: []js_ast.Decl{{
Binding: js_ast.Binding{Loc: loc, Data: &js_ast.BIdentifier{Ref: namespaceRef}},
ValueOrNil: js_ast.Expr{Loc: record.Range.Loc, Data: &js_ast.ERequireString{
ImportRecordIndex: importRecordIndex,
}},
}}},
})
return true
}
// We don't need a call to "require()" if this is a self-import inside a
// CommonJS-style module, since we can just reference the exports directly.
if repr.AST.ExportsKind == js_ast.ExportsCommonJS && js_ast.FollowSymbols(c.graph.Symbols, namespaceRef) == repr.AST.ExportsRef {
return true
}
otherFile := &c.graph.Files[record.SourceIndex.GetIndex()]
otherRepr := otherFile.InputFile.Repr.(*graph.JSRepr)
switch otherRepr.Meta.Wrap {
case graph.WrapNone:
// Remove the statement entirely if this module is not wrapped
case graph.WrapCJS:
// Replace the statement with a call to "require()"
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{
Loc: loc,
Data: &js_ast.SLocal{Decls: []js_ast.Decl{{
Binding: js_ast.Binding{Loc: loc, Data: &js_ast.BIdentifier{Ref: namespaceRef}},
ValueOrNil: js_ast.Expr{Loc: record.Range.Loc, Data: &js_ast.ERequireString{
ImportRecordIndex: importRecordIndex,
}},
}}},
})
case graph.WrapESM:
// Ignore this file if it's not included in the bundle. This can happen for
// wrapped ESM files but not for wrapped CommonJS files because we allow
// tree shaking inside wrapped ESM files.
if !otherFile.IsLive {
break
}
// Replace the statement with a call to "init()"
value := js_ast.Expr{Loc: loc, Data: &js_ast.ECall{Target: js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: otherRepr.AST.WrapperRef}}}}
if otherRepr.Meta.IsAsyncOrHasAsyncDependency {
// This currently evaluates sibling dependencies in serial instead of in
// parallel, which is incorrect. This should be changed to store a promise
// and await all stored promises after all imports but before any code.
value.Data = &js_ast.EAwait{Value: value}
}
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: value}})
}
return true
}
func (c *linkerContext) convertStmtsForChunk(sourceIndex uint32, stmtList *stmtList, partStmts []js_ast.Stmt) {
file := &c.graph.Files[sourceIndex]
shouldStripExports := c.options.Mode != config.ModePassThrough || !file.IsEntryPoint()
repr := file.InputFile.Repr.(*graph.JSRepr)
shouldExtractESMStmtsForWrap := repr.Meta.Wrap != graph.WrapNone
for _, stmt := range partStmts {
switch s := stmt.Data.(type) {
case *js_ast.SImport:
// "import * as ns from 'path'"
// "import {foo} from 'path'"
if c.shouldRemoveImportExportStmt(sourceIndex, stmtList, stmt.Loc, s.NamespaceRef, s.ImportRecordIndex) {
continue
}
// Make sure these don't end up in the wrapper closure
if shouldExtractESMStmtsForWrap {
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, stmt)
continue
}
case *js_ast.SExportStar:
// "export * as ns from 'path'"
if s.Alias != nil {
if c.shouldRemoveImportExportStmt(sourceIndex, stmtList, stmt.Loc, s.NamespaceRef, s.ImportRecordIndex) {
continue
}
if shouldStripExports {
// Turn this statement into "import * as ns from 'path'"
stmt.Data = &js_ast.SImport{
NamespaceRef: s.NamespaceRef,
StarNameLoc: &s.Alias.Loc,
ImportRecordIndex: s.ImportRecordIndex,
}
}
// Make sure these don't end up in the wrapper closure
if shouldExtractESMStmtsForWrap {
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, stmt)
continue
}
break
}
// "export * from 'path'"
if !shouldStripExports {
break
}
record := &repr.AST.ImportRecords[s.ImportRecordIndex]
// Is this export star evaluated at run time?
if !record.SourceIndex.IsValid() && c.options.OutputFormat.KeepES6ImportExportSyntax() {
if record.CallsRunTimeReExportFn {
// Turn this statement into "import * as ns from 'path'"
stmt.Data = &js_ast.SImport{
NamespaceRef: s.NamespaceRef,
StarNameLoc: &logger.Loc{Start: stmt.Loc.Start},
ImportRecordIndex: s.ImportRecordIndex,
}
// Prefix this module with "__reExport(exports, ns)"
exportStarRef := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr).AST.ModuleScope.Members["__reExport"].Ref
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{
Loc: stmt.Loc,
Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.ECall{
Target: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: exportStarRef}},
Args: []js_ast.Expr{
{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}},
{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: s.NamespaceRef}},
},
}}},
})
// Make sure these don't end up in the wrapper closure
if shouldExtractESMStmtsForWrap {
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, stmt)
continue
}
}
} else {
if record.SourceIndex.IsValid() {
if otherRepr := c.graph.Files[record.SourceIndex.GetIndex()].InputFile.Repr.(*graph.JSRepr); otherRepr.Meta.Wrap == graph.WrapESM {
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{Loc: stmt.Loc,
Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.ECall{
Target: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: otherRepr.AST.WrapperRef}}}}}})
}
}
if record.CallsRunTimeReExportFn {
var target js_ast.E
if record.SourceIndex.IsValid() {
if otherRepr := c.graph.Files[record.SourceIndex.GetIndex()].InputFile.Repr.(*graph.JSRepr); otherRepr.AST.ExportsKind == js_ast.ExportsESMWithDynamicFallback {
// Prefix this module with "__reExport(exports, otherExports)"
target = &js_ast.EIdentifier{Ref: otherRepr.AST.ExportsRef}
}
}
if target == nil {
// Prefix this module with "__reExport(exports, require(path))"
target = &js_ast.ERequireString{
ImportRecordIndex: s.ImportRecordIndex,
}
}
exportStarRef := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr).AST.ModuleScope.Members["__reExport"].Ref
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{
Loc: stmt.Loc,
Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.ECall{
Target: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: exportStarRef}},
Args: []js_ast.Expr{
{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}},
{Loc: record.Range.Loc, Data: target},
},
}}},
})
}
// Remove the export star statement
continue
}
case *js_ast.SExportFrom:
// "export {foo} from 'path'"
if c.shouldRemoveImportExportStmt(sourceIndex, stmtList, stmt.Loc, s.NamespaceRef, s.ImportRecordIndex) {
continue
}
if shouldStripExports {
// Turn this statement into "import {foo} from 'path'"
for i, item := range s.Items {
s.Items[i].Alias = item.OriginalName
}
stmt.Data = &js_ast.SImport{
NamespaceRef: s.NamespaceRef,
Items: &s.Items,
ImportRecordIndex: s.ImportRecordIndex,
IsSingleLine: s.IsSingleLine,
}
}
// Make sure these don't end up in the wrapper closure
if shouldExtractESMStmtsForWrap {
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, stmt)
continue
}
case *js_ast.SExportClause:
if shouldStripExports {
// Remove export statements entirely
continue
}
// Make sure these don't end up in the wrapper closure
if shouldExtractESMStmtsForWrap {
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, stmt)
continue
}
case *js_ast.SFunction:
// Strip the "export" keyword while bundling
if shouldStripExports && s.IsExport {
// Be careful to not modify the original statement
clone := *s
clone.IsExport = false
stmt.Data = &clone
}
case *js_ast.SClass:
if shouldStripExports && s.IsExport {
// Be careful to not modify the original statement
clone := *s
clone.IsExport = false
stmt.Data = &clone
}
case *js_ast.SLocal:
if shouldStripExports && s.IsExport {
// Be careful to not modify the original statement
clone := *s
clone.IsExport = false
stmt.Data = &clone
}
case *js_ast.SExportDefault:
// If we're bundling, convert "export default" into a normal declaration
if shouldStripExports {
switch s2 := s.Value.Data.(type) {
case *js_ast.SExpr:
// "export default foo;" => "var default = foo;"
stmt = js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SLocal{Decls: []js_ast.Decl{
{Binding: js_ast.Binding{Loc: s.DefaultName.Loc, Data: &js_ast.BIdentifier{Ref: s.DefaultName.Ref}}, ValueOrNil: s2.Value},
}}}
case *js_ast.SFunction:
// "export default function() {}" => "function default() {}"
// "export default function foo() {}" => "function foo() {}"
// Be careful to not modify the original statement
s2 = &js_ast.SFunction{Fn: s2.Fn}
s2.Fn.Name = &s.DefaultName
stmt = js_ast.Stmt{Loc: s.Value.Loc, Data: s2}
case *js_ast.SClass:
// "export default class {}" => "class default {}"
// "export default class Foo {}" => "class Foo {}"
// Be careful to not modify the original statement
s2 = &js_ast.SClass{Class: s2.Class}
s2.Class.Name = &s.DefaultName
stmt = js_ast.Stmt{Loc: s.Value.Loc, Data: s2}
default:
panic("Internal error")
}
}
}
stmtList.insideWrapperSuffix = append(stmtList.insideWrapperSuffix, stmt)
}
}
// "var a = 1; var b = 2;" => "var a = 1, b = 2;"
func mergeAdjacentLocalStmts(stmts []js_ast.Stmt) []js_ast.Stmt {
if len(stmts) == 0 {
return stmts
}
didMergeWithPreviousLocal := false
end := 1
for _, stmt := range stmts[1:] {
// Try to merge with the previous variable statement
if after, ok := stmt.Data.(*js_ast.SLocal); ok {
if before, ok := stmts[end-1].Data.(*js_ast.SLocal); ok {
// It must be the same kind of variable statement (i.e. let/var/const)
if before.Kind == after.Kind && before.IsExport == after.IsExport {
if didMergeWithPreviousLocal {
// Avoid O(n^2) behavior for repeated variable declarations
before.Decls = append(before.Decls, after.Decls...)
} else {
// Be careful to not modify the original statement
didMergeWithPreviousLocal = true
clone := *before
clone.Decls = make([]js_ast.Decl, 0, len(before.Decls)+len(after.Decls))
clone.Decls = append(clone.Decls, before.Decls...)
clone.Decls = append(clone.Decls, after.Decls...)
stmts[end-1].Data = &clone
}
continue
}
}
}
// Otherwise, append a normal statement
didMergeWithPreviousLocal = false
stmts[end] = stmt
end++
}
return stmts[:end]
}
type stmtList struct {
// These statements come first, and can be inside the wrapper
insideWrapperPrefix []js_ast.Stmt
// These statements come last, and can be inside the wrapper
insideWrapperSuffix []js_ast.Stmt
outsideWrapperPrefix []js_ast.Stmt
}
type compileResultJS struct {
js_printer.PrintResult
sourceIndex uint32
// This is the line and column offset since the previous JavaScript string
// or the start of the file if this is the first JavaScript string.
generatedOffset sourcemap.LineColumnOffset
}
func (c *linkerContext) requireOrImportMetaForSource(sourceIndex uint32) (meta js_printer.RequireOrImportMeta) {
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
meta.WrapperRef = repr.AST.WrapperRef
meta.IsWrapperAsync = repr.Meta.IsAsyncOrHasAsyncDependency
if repr.Meta.Wrap == graph.WrapESM {
meta.ExportsRef = repr.AST.ExportsRef
} else {
meta.ExportsRef = js_ast.InvalidRef
}
return
}
func (c *linkerContext) generateCodeForFileInChunkJS(
r renamer.Renamer,
waitGroup *sync.WaitGroup,
partRange partRange,
entryBits helpers.BitSet,
chunkAbsDir string,
toCommonJSRef js_ast.Ref,
toESMRef js_ast.Ref,
runtimeRequireRef js_ast.Ref,
result *compileResultJS,
dataForSourceMaps []dataForSourceMap,
) {
defer c.recoverInternalError(waitGroup, partRange.sourceIndex)
file := &c.graph.Files[partRange.sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
nsExportPartIndex := js_ast.NSExportPartIndex
needsWrapper := false
stmtList := stmtList{}
// The top-level directive must come first (the non-wrapped case is handled
// by the chunk generation code, although only for the entry point)
if repr.AST.Directive != "" && repr.Meta.Wrap != graph.WrapNone && !file.IsEntryPoint() {
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{
Data: &js_ast.SDirective{Value: js_lexer.StringToUTF16(repr.AST.Directive)},
})
}
// Make sure the generated call to "__export(exports, ...)" comes first
// before anything else.
if nsExportPartIndex >= partRange.partIndexBegin && nsExportPartIndex < partRange.partIndexEnd &&
repr.AST.Parts[nsExportPartIndex].IsLive {
c.convertStmtsForChunk(partRange.sourceIndex, &stmtList, repr.AST.Parts[nsExportPartIndex].Stmts)
// Move everything to the prefix list
if repr.Meta.Wrap == graph.WrapESM {
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, stmtList.insideWrapperSuffix...)
} else {
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, stmtList.insideWrapperSuffix...)
}
stmtList.insideWrapperSuffix = nil
}
// Add all other parts in this chunk
for partIndex := partRange.partIndexBegin; partIndex < partRange.partIndexEnd; partIndex++ {
part := repr.AST.Parts[partIndex]
if !repr.AST.Parts[partIndex].IsLive {
// Skip the part if it's not in this chunk
continue
}
if uint32(partIndex) == nsExportPartIndex {
// Skip the generated call to "__export()" that was extracted above
continue
}
// Mark if we hit the dummy part representing the wrapper
if uint32(partIndex) == repr.Meta.WrapperPartIndex.GetIndex() {
needsWrapper = true
continue
}
c.convertStmtsForChunk(partRange.sourceIndex, &stmtList, part.Stmts)
}
// Hoist all import statements before any normal statements. ES6 imports
// are different than CommonJS imports. All modules imported via ES6 import
// statements are evaluated before the module doing the importing is
// evaluated (well, except for cyclic import scenarios). We need to preserve
// these semantics even when modules imported via ES6 import statements end
// up being CommonJS modules.
stmts := stmtList.insideWrapperSuffix
if len(stmtList.insideWrapperPrefix) > 0 {
stmts = append(stmtList.insideWrapperPrefix, stmts...)
}
if c.options.MangleSyntax {
stmts = mergeAdjacentLocalStmts(stmts)
}
// Optionally wrap all statements in a closure
if needsWrapper {
switch repr.Meta.Wrap {
case graph.WrapCJS:
// Only include the arguments that are actually used
args := []js_ast.Arg{}
if repr.AST.UsesExportsRef || repr.AST.UsesModuleRef {
args = append(args, js_ast.Arg{Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: repr.AST.ExportsRef}}})
if repr.AST.UsesModuleRef {
args = append(args, js_ast.Arg{Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: repr.AST.ModuleRef}}})
}
}
var cjsArgs []js_ast.Expr
if c.options.ProfilerNames {
// "__commonJS({ 'file.js'(exports, module) { ... } })"
cjsArgs = []js_ast.Expr{{Data: &js_ast.EObject{Properties: []js_ast.Property{{
IsMethod: !c.options.UnsupportedJSFeatures.Has(compat.ObjectExtensions),
Key: js_ast.Expr{Data: &js_ast.EString{Value: js_lexer.StringToUTF16(file.InputFile.Source.PrettyPath)}},
ValueOrNil: js_ast.Expr{Data: &js_ast.EFunction{Fn: js_ast.Fn{Args: args, Body: js_ast.FnBody{Stmts: stmts}}}},
}}}}}
} else if c.options.UnsupportedJSFeatures.Has(compat.Arrow) {
// "__commonJS(function (exports, module) { ... })"
cjsArgs = []js_ast.Expr{{Data: &js_ast.EFunction{Fn: js_ast.Fn{Args: args, Body: js_ast.FnBody{Stmts: stmts}}}}}
} else {
// "__commonJS((exports, module) => { ... })"
cjsArgs = []js_ast.Expr{{Data: &js_ast.EArrow{Args: args, Body: js_ast.FnBody{Stmts: stmts}}}}
}
value := js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.cjsRuntimeRef}},
Args: cjsArgs,
}}
// "var require_foo = __commonJS(...);"
stmts = append(stmtList.outsideWrapperPrefix, js_ast.Stmt{Data: &js_ast.SLocal{
Decls: []js_ast.Decl{{
Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: repr.AST.WrapperRef}},
ValueOrNil: value,
}},
}})
case graph.WrapESM:
// The wrapper only needs to be "async" if there is a transitive async
// dependency. For correctness, we must not use "async" if the module
// isn't async because then calling "require()" on that module would
// swallow any exceptions thrown during module initialization.
isAsync := repr.Meta.IsAsyncOrHasAsyncDependency
// Hoist all top-level "var" and "function" declarations out of the closure
var decls []js_ast.Decl
end := 0
for _, stmt := range stmts {
switch s := stmt.Data.(type) {
case *js_ast.SLocal:
// Convert the declarations to assignments
wrapIdentifier := func(loc logger.Loc, ref js_ast.Ref) js_ast.Expr {
decls = append(decls, js_ast.Decl{Binding: js_ast.Binding{Loc: loc, Data: &js_ast.BIdentifier{Ref: ref}}})
return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: ref}}
}
var value js_ast.Expr
for _, decl := range s.Decls {
binding := js_ast.ConvertBindingToExpr(decl.Binding, wrapIdentifier)
if decl.ValueOrNil.Data != nil {
value = js_ast.JoinWithComma(value, js_ast.Assign(binding, decl.ValueOrNil))
}
}
if value.Data == nil {
continue
}
stmt = js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SExpr{Value: value}}
case *js_ast.SFunction:
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, stmt)
continue
}
stmts[end] = stmt
end++
}
stmts = stmts[:end]
var esmArgs []js_ast.Expr
if c.options.ProfilerNames {
// "__esm({ 'file.js'() { ... } })"
esmArgs = []js_ast.Expr{{Data: &js_ast.EObject{Properties: []js_ast.Property{{
IsMethod: !c.options.UnsupportedJSFeatures.Has(compat.ObjectExtensions),
Key: js_ast.Expr{Data: &js_ast.EString{Value: js_lexer.StringToUTF16(file.InputFile.Source.PrettyPath)}},
ValueOrNil: js_ast.Expr{Data: &js_ast.EFunction{Fn: js_ast.Fn{Body: js_ast.FnBody{Stmts: stmts}, IsAsync: isAsync}}},
}}}}}
} else if c.options.UnsupportedJSFeatures.Has(compat.Arrow) {
// "__esm(function () { ... })"
esmArgs = []js_ast.Expr{{Data: &js_ast.EFunction{Fn: js_ast.Fn{Body: js_ast.FnBody{Stmts: stmts}, IsAsync: isAsync}}}}
} else {
// "__esm(() => { ... })"
esmArgs = []js_ast.Expr{{Data: &js_ast.EArrow{Body: js_ast.FnBody{Stmts: stmts}, IsAsync: isAsync}}}
}
value := js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.esmRuntimeRef}},
Args: esmArgs,
}}
// "var foo, bar;"
if !c.options.MangleSyntax && len(decls) > 0 {
stmtList.outsideWrapperPrefix = append(stmtList.outsideWrapperPrefix, js_ast.Stmt{Data: &js_ast.SLocal{
Decls: decls,
}})
decls = nil
}
// "var init_foo = __esm(...);"
stmts = append(stmtList.outsideWrapperPrefix, js_ast.Stmt{Data: &js_ast.SLocal{
Decls: append(decls, js_ast.Decl{
Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: repr.AST.WrapperRef}},
ValueOrNil: value,
}),
}})
}
}
// Only generate a source map if needed
var addSourceMappings bool
var inputSourceMap *sourcemap.SourceMap
var lineOffsetTables []sourcemap.LineOffsetTable
if file.InputFile.Loader.CanHaveSourceMap() && c.options.SourceMap != config.SourceMapNone {
addSourceMappings = true
inputSourceMap = file.InputFile.InputSourceMap
lineOffsetTables = dataForSourceMaps[partRange.sourceIndex].lineOffsetTables
}
// Indent the file if everything is wrapped in an IIFE
indent := 0
if c.options.OutputFormat == config.FormatIIFE {
indent++
}
// Convert the AST to JavaScript code
printOptions := js_printer.Options{
Indent: indent,
OutputFormat: c.options.OutputFormat,
RemoveWhitespace: c.options.RemoveWhitespace,
MangleSyntax: c.options.MangleSyntax,
ASCIIOnly: c.options.ASCIIOnly,
ToCommonJSRef: toCommonJSRef,
ToESMRef: toESMRef,
RuntimeRequireRef: runtimeRequireRef,
LegalComments: c.options.LegalComments,
UnsupportedFeatures: c.options.UnsupportedJSFeatures,
AddSourceMappings: addSourceMappings,
InputSourceMap: inputSourceMap,
LineOffsetTables: lineOffsetTables,
RequireOrImportMetaForSource: c.requireOrImportMetaForSource,
}
tree := repr.AST
tree.Directive = "" // This is handled elsewhere
tree.Parts = []js_ast.Part{{Stmts: stmts}}
*result = compileResultJS{
PrintResult: js_printer.Print(tree, c.graph.Symbols, r, printOptions),
sourceIndex: partRange.sourceIndex,
}
waitGroup.Done()
}
func (c *linkerContext) generateEntryPointTailJS(
r renamer.Renamer,
toCommonJSRef js_ast.Ref,
toESMRef js_ast.Ref,
sourceIndex uint32,
) (result compileResultJS) {
file := &c.graph.Files[sourceIndex]
repr := file.InputFile.Repr.(*graph.JSRepr)
var stmts []js_ast.Stmt
switch c.options.OutputFormat {
case config.FormatPreserve:
if repr.Meta.Wrap != graph.WrapNone {
// "require_foo();"
// "init_foo();"
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SExpr{Value: js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}},
}}}})
}
case config.FormatIIFE:
if repr.Meta.Wrap == graph.WrapCJS {
if len(c.options.GlobalName) > 0 {
// "return require_foo();"
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SReturn{ValueOrNil: js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}},
}}}})
} else {
// "require_foo();"
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SExpr{Value: js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}},
}}}})
}
} else {
if repr.Meta.Wrap == graph.WrapESM {
// "init_foo();"
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SExpr{Value: js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}},
}}}})
}
if repr.Meta.ForceIncludeExportsForEntryPoint {
// "return __toCommonJS(exports);"
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SReturn{
ValueOrNil: js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: toCommonJSRef}},
Args: []js_ast.Expr{{Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}}},
}},
}})
}
}
case config.FormatCommonJS:
if repr.Meta.Wrap == graph.WrapCJS {
// "module.exports = require_foo();"
stmts = append(stmts, js_ast.AssignStmt(
js_ast.Expr{Data: &js_ast.EDot{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.unboundModuleRef}},
Name: "exports",
}},
js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}},
}},
))
} else {
if repr.Meta.Wrap == graph.WrapESM {
// "init_foo();"
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SExpr{Value: js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}},
}}}})
}
// Decorate "module.exports" with the "__esModule" flag to indicate that
// we used to be an ES module. This is done by wrapping the exports object
// instead of by mutating the exports object because other modules in the
// bundle (including the entry point module) may do "import * as" to get
// access to the exports object and should NOT see the "__esModule" flag.
if repr.Meta.ForceIncludeExportsForEntryPoint {
// "module.exports = __toCommonJS(exports);"
stmts = append(stmts, js_ast.AssignStmt(
js_ast.Expr{Data: &js_ast.EDot{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.unboundModuleRef}},
Name: "exports",
}},
js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: toCommonJSRef}},
Args: []js_ast.Expr{{Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}}},
}},
))
}
}
// If we are generating CommonJS for node, encode the known export names in
// a form that node can understand them. This relies on the specific behavior
// of this parser, which the node project uses to detect named exports in
// CommonJS files: https://github.com/guybedford/cjs-module-lexer. Think of
// this code as an annotation for that parser.
if c.options.Platform == config.PlatformNode && len(repr.Meta.SortedAndFilteredExportAliases) > 0 {
// Add a comment since otherwise people will surely wonder what this is.
// This annotation means you can do this and have it work:
//
// import { name } from './file-from-esbuild.cjs'
//
// when "file-from-esbuild.cjs" looks like this:
//
// __export(exports, { name: () => name });
// 0 && (module.exports = {name});
//
// The maintainer of "cjs-module-lexer" is receptive to adding esbuild-
// friendly patterns to this library. However, this library has already
// shipped in node and using existing patterns instead of defining new
// patterns is maximally compatible.
//
// An alternative to doing this could be to use "Object.defineProperties"
// instead of "__export" but support for that would need to be added to
// "cjs-module-lexer" and then we would need to be ok with not supporting
// older versions of node that don't have that newly-added support.
if !c.options.RemoveWhitespace {
stmts = append(stmts,
js_ast.Stmt{Data: &js_ast.SComment{Text: `// Annotate the CommonJS export names for ESM import in node:`}},
)
}
// "{a, b, if: null}"
var moduleExports []js_ast.Property
for _, export := range repr.Meta.SortedAndFilteredExportAliases {
if export == "default" {
// In node the default export is always "module.exports" regardless of
// what the annotation says. So don't bother generating "default".
continue
}
// "{if: null}"
var valueOrNil js_ast.Expr
if _, ok := js_lexer.Keywords[export]; ok {
// Make sure keywords don't cause a syntax error. This has to map to
// "null" instead of something shorter like "0" because the library
// "cjs-module-lexer" only supports identifiers in this position, and
// it thinks "null" is an identifier.
valueOrNil = js_ast.Expr{Data: js_ast.ENullShared}
}
moduleExports = append(moduleExports, js_ast.Property{
Key: js_ast.Expr{Data: &js_ast.EString{Value: js_lexer.StringToUTF16(export)}},
ValueOrNil: valueOrNil,
})
}
// "0 && (module.exports = {a, b, if: null});"
expr := js_ast.Expr{Data: &js_ast.EBinary{
Op: js_ast.BinOpLogicalAnd,
Left: js_ast.Expr{Data: &js_ast.ENumber{Value: 0}},
Right: js_ast.Assign(
js_ast.Expr{Data: &js_ast.EDot{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.unboundModuleRef}},
Name: "exports",
}},
js_ast.Expr{Data: &js_ast.EObject{Properties: moduleExports}},
),
}}
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SExpr{Value: expr}})
}
case config.FormatESModule:
if repr.Meta.Wrap == graph.WrapCJS {
// "export default require_foo();"
stmts = append(stmts, js_ast.Stmt{
Data: &js_ast.SExportDefault{Value: js_ast.Stmt{
Data: &js_ast.SExpr{Value: js_ast.Expr{
Data: &js_ast.ECall{Target: js_ast.Expr{
Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}}}}}}}})
} else {
if repr.Meta.Wrap == graph.WrapESM {
if repr.Meta.IsAsyncOrHasAsyncDependency {
// "await init_foo();"
stmts = append(stmts, js_ast.Stmt{
Data: &js_ast.SExpr{Value: js_ast.Expr{
Data: &js_ast.EAwait{Value: js_ast.Expr{
Data: &js_ast.ECall{Target: js_ast.Expr{
Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}}}}}}}})
} else {
// "init_foo();"
stmts = append(stmts, js_ast.Stmt{
Data: &js_ast.SExpr{
Value: js_ast.Expr{Data: &js_ast.ECall{Target: js_ast.Expr{
Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}}}}}})
}
}
if len(repr.Meta.SortedAndFilteredExportAliases) > 0 {
// If the output format is ES6 modules and we're an entry point, generate an
// ES6 export statement containing all exports. Except don't do that if this
// entry point is a CommonJS-style module, since that would generate an ES6
// export statement that's not top-level. Instead, we will export the CommonJS
// exports as a default export later on.
var items []js_ast.ClauseItem
for i, alias := range repr.Meta.SortedAndFilteredExportAliases {
export := repr.Meta.ResolvedExports[alias]
// If this is an export of an import, reference the symbol that the import
// was eventually resolved to. We need to do this because imports have
// already been resolved by this point, so we can't generate a new import
// and have that be resolved later.
if importData, ok := c.graph.Files[export.SourceIndex].InputFile.Repr.(*graph.JSRepr).Meta.ImportsToBind[export.Ref]; ok {
export.Ref = importData.Ref
export.SourceIndex = importData.SourceIndex
}
// Exports of imports need EImportIdentifier in case they need to be re-
// written to a property access later on
if c.graph.Symbols.Get(export.Ref).NamespaceAlias != nil {
// Create both a local variable and an export clause for that variable.
// The local variable is initialized with the initial value of the
// export. This isn't fully correct because it's a "dead" binding and
// doesn't update with the "live" value as it changes. But ES6 modules
// don't have any syntax for bare named getter functions so this is the
// best we can do.
//
// These input files:
//
// // entry_point.js
// export {foo} from './cjs-format.js'
//
// // cjs-format.js
// Object.defineProperty(exports, 'foo', {
// enumerable: true,
// get: () => Math.random(),
// })
//
// Become this output file:
//
// // cjs-format.js
// var require_cjs_format = __commonJS((exports) => {
// Object.defineProperty(exports, "foo", {
// enumerable: true,
// get: () => Math.random()
// });
// });
//
// // entry_point.js
// var cjs_format = __toESM(require_cjs_format());
// var export_foo = cjs_format.foo;
// export {
// export_foo as foo
// };
//
tempRef := repr.Meta.CJSExportCopies[i]
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SLocal{
Decls: []js_ast.Decl{{
Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: tempRef}},
ValueOrNil: js_ast.Expr{Data: &js_ast.EImportIdentifier{Ref: export.Ref}},
}},
}})
items = append(items, js_ast.ClauseItem{
Name: js_ast.LocRef{Ref: tempRef},
Alias: alias,
})
} else {
// Local identifiers can be exported using an export clause. This is done
// this way instead of leaving the "export" keyword on the local declaration
// itself both because it lets the local identifier be minified and because
// it works transparently for re-exports across files.
//
// These input files:
//
// // entry_point.js
// export * from './esm-format.js'
//
// // esm-format.js
// export let foo = 123
//
// Become this output file:
//
// // esm-format.js
// let foo = 123;
//
// // entry_point.js
// export {
// foo
// };
//
items = append(items, js_ast.ClauseItem{
Name: js_ast.LocRef{Ref: export.Ref},
Alias: alias,
})
}
}
stmts = append(stmts, js_ast.Stmt{Data: &js_ast.SExportClause{Items: items}})
}
}
}
if len(stmts) == 0 {
return
}
tree := repr.AST
tree.Parts = []js_ast.Part{{Stmts: stmts}}
// Indent the file if everything is wrapped in an IIFE
indent := 0
if c.options.OutputFormat == config.FormatIIFE {
indent++
}
// Convert the AST to JavaScript code
printOptions := js_printer.Options{
Indent: indent,
OutputFormat: c.options.OutputFormat,
RemoveWhitespace: c.options.RemoveWhitespace,
MangleSyntax: c.options.MangleSyntax,
ASCIIOnly: c.options.ASCIIOnly,
ToCommonJSRef: toCommonJSRef,
ToESMRef: toESMRef,
LegalComments: c.options.LegalComments,
UnsupportedFeatures: c.options.UnsupportedJSFeatures,
RequireOrImportMetaForSource: c.requireOrImportMetaForSource,
}
result.PrintResult = js_printer.Print(tree, c.graph.Symbols, r, printOptions)
return
}
func (c *linkerContext) renameSymbolsInChunk(chunk *chunkInfo, filesInOrder []uint32, timer *helpers.Timer) renamer.Renamer {
if c.options.MinifyIdentifiers {
timer.Begin("Minify symbols")
defer timer.End("Minify symbols")
} else {
timer.Begin("Rename symbols")
defer timer.End("Rename symbols")
}
// Determine the reserved names (e.g. can't generate the name "if")
timer.Begin("Compute reserved names")
moduleScopes := make([]*js_ast.Scope, len(filesInOrder))
for i, sourceIndex := range filesInOrder {
moduleScopes[i] = c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr).AST.ModuleScope
}
reservedNames := renamer.ComputeReservedNames(moduleScopes, c.graph.Symbols)
// These are used to implement bundling, and need to be free for use
if c.options.Mode != config.ModePassThrough {
reservedNames["require"] = 1
reservedNames["Promise"] = 1
}
timer.End("Compute reserved names")
// Make sure imports get a chance to be renamed too
var sortedImportsFromOtherChunks stableRefArray
for _, imports := range chunk.chunkRepr.(*chunkReprJS).importsFromOtherChunks {
for _, item := range imports {
sortedImportsFromOtherChunks = append(sortedImportsFromOtherChunks, stableRef{
StableSourceIndex: c.graph.StableSourceIndices[item.ref.SourceIndex],
Ref: item.ref,
})
}
}
sort.Sort(sortedImportsFromOtherChunks)
// Minification uses frequency analysis to give shorter names to more frequent symbols
if c.options.MinifyIdentifiers {
// Determine the first top-level slot (i.e. not in a nested scope)
var firstTopLevelSlots js_ast.SlotCounts
for _, sourceIndex := range filesInOrder {
firstTopLevelSlots.UnionMax(c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr).AST.NestedScopeSlotCounts)
}
r := renamer.NewMinifyRenamer(c.graph.Symbols, firstTopLevelSlots, reservedNames)
// Accumulate nested symbol usage counts
timer.Begin("Accumulate symbol counts")
timer.Begin("Parallel phase")
allTopLevelSymbols := make([]renamer.DeferredTopLevelSymbolArray, len(filesInOrder))
stableSourceIndices := c.graph.StableSourceIndices
freq := js_ast.CharFreq{}
waitGroup := sync.WaitGroup{}
waitGroup.Add(len(filesInOrder))
for i, sourceIndex := range filesInOrder {
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
// Do this outside of the goroutine because it's not atomic
if repr.AST.CharFreq != nil {
freq.Include(repr.AST.CharFreq)
}
go func(topLevelSymbols *renamer.DeferredTopLevelSymbolArray, repr *graph.JSRepr) {
if repr.AST.UsesExportsRef {
r.AccumulateSymbolCount(topLevelSymbols, repr.AST.ExportsRef, 1, stableSourceIndices)
}
if repr.AST.UsesModuleRef {
r.AccumulateSymbolCount(topLevelSymbols, repr.AST.ModuleRef, 1, stableSourceIndices)
}
for partIndex, part := range repr.AST.Parts {
if !repr.AST.Parts[partIndex].IsLive {
// Skip the part if it's not in this chunk
continue
}
// Accumulate symbol use counts
r.AccumulateSymbolUseCounts(topLevelSymbols, part.SymbolUses, stableSourceIndices)
// Make sure to also count the declaration in addition to the uses
for _, declared := range part.DeclaredSymbols {
r.AccumulateSymbolCount(topLevelSymbols, declared.Ref, 1, stableSourceIndices)
}
}
sort.Sort(topLevelSymbols)
waitGroup.Done()
}(&allTopLevelSymbols[i], repr)
}
waitGroup.Wait()
timer.End("Parallel phase")
// Accumulate top-level symbol usage counts
timer.Begin("Serial phase")
capacity := len(sortedImportsFromOtherChunks)
for _, array := range allTopLevelSymbols {
capacity += len(array)
}
topLevelSymbols := make(renamer.DeferredTopLevelSymbolArray, 0, capacity)
for _, stable := range sortedImportsFromOtherChunks {
r.AccumulateSymbolCount(&topLevelSymbols, stable.Ref, 1, stableSourceIndices)
}
for _, array := range allTopLevelSymbols {
topLevelSymbols = append(topLevelSymbols, array...)
}
r.AllocateTopLevelSymbolSlots(topLevelSymbols)
timer.End("Serial phase")
timer.End("Accumulate symbol counts")
// Add all of the character frequency histograms for all files in this
// chunk together, then use it to compute the character sequence used to
// generate minified names. This results in slightly better gzip compression
// over assigning minified names in order (i.e. "a b c ..."). Even though
// it's a very small win, we still do it because it's simple to do and very
// cheap to compute.
minifier := freq.Compile()
timer.Begin("Assign names by frequency")
r.AssignNamesByFrequency(&minifier)
timer.End("Assign names by frequency")
return r
}
// When we're not minifying, just append numbers to symbol names to avoid collisions
r := renamer.NewNumberRenamer(c.graph.Symbols, reservedNames)
nestedScopes := make(map[uint32][]*js_ast.Scope)
timer.Begin("Add top-level symbols")
for _, stable := range sortedImportsFromOtherChunks {
r.AddTopLevelSymbol(stable.Ref)
}
for _, sourceIndex := range filesInOrder {
repr := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
var scopes []*js_ast.Scope
// Modules wrapped in a CommonJS closure look like this:
//
// // foo.js
// var require_foo = __commonJS((exports, module) => {
// exports.foo = 123;
// });
//
// The symbol "require_foo" is stored in "file.ast.WrapperRef". We want
// to be able to minify everything inside the closure without worrying
// about collisions with other CommonJS modules. Set up the scopes such
// that it appears as if the file was structured this way all along. It's
// not completely accurate (e.g. we don't set the parent of the module
// scope to this new top-level scope) but it's good enough for the
// renaming code.
if repr.Meta.Wrap == graph.WrapCJS {
r.AddTopLevelSymbol(repr.AST.WrapperRef)
// External import statements will be hoisted outside of the CommonJS
// wrapper if the output format supports import statements. We need to
// add those symbols to the top-level scope to avoid causing name
// collisions. This code special-cases only those symbols.
if c.options.OutputFormat.KeepES6ImportExportSyntax() {
for _, part := range repr.AST.Parts {
for _, stmt := range part.Stmts {
switch s := stmt.Data.(type) {
case *js_ast.SImport:
if !repr.AST.ImportRecords[s.ImportRecordIndex].SourceIndex.IsValid() {
r.AddTopLevelSymbol(s.NamespaceRef)
if s.DefaultName != nil {
r.AddTopLevelSymbol(s.DefaultName.Ref)
}
if s.Items != nil {
for _, item := range *s.Items {
r.AddTopLevelSymbol(item.Name.Ref)
}
}
}
case *js_ast.SExportStar:
if !repr.AST.ImportRecords[s.ImportRecordIndex].SourceIndex.IsValid() {
r.AddTopLevelSymbol(s.NamespaceRef)
}
case *js_ast.SExportFrom:
if !repr.AST.ImportRecords[s.ImportRecordIndex].SourceIndex.IsValid() {
r.AddTopLevelSymbol(s.NamespaceRef)
for _, item := range s.Items {
r.AddTopLevelSymbol(item.Name.Ref)
}
}
}
}
}
}
nestedScopes[sourceIndex] = []*js_ast.Scope{repr.AST.ModuleScope}
continue
}
// Modules wrapped in an ESM closure look like this:
//
// // foo.js
// var foo, foo_exports = {};
// __export(foo_exports, {
// foo: () => foo
// });
// let init_foo = __esm(() => {
// foo = 123;
// });
//
// The symbol "init_foo" is stored in "file.ast.WrapperRef". We need to
// minify everything inside the closure without introducing a new scope
// since all top-level variables will be hoisted outside of the closure.
if repr.Meta.Wrap == graph.WrapESM {
r.AddTopLevelSymbol(repr.AST.WrapperRef)
}
// Rename each top-level symbol declaration in this chunk
for partIndex, part := range repr.AST.Parts {
if repr.AST.Parts[partIndex].IsLive {
for _, declared := range part.DeclaredSymbols {
if declared.IsTopLevel {
r.AddTopLevelSymbol(declared.Ref)
}
}
scopes = append(scopes, part.Scopes...)
}
}
nestedScopes[sourceIndex] = scopes
}
timer.End("Add top-level symbols")
// Recursively rename symbols in child scopes now that all top-level
// symbols have been renamed. This is done in parallel because the symbols
// inside nested scopes are independent and can't conflict.
timer.Begin("Assign names by scope")
r.AssignNamesByScope(nestedScopes)
timer.End("Assign names by scope")
return r
}
func (c *linkerContext) generateChunkJS(chunks []chunkInfo, chunkIndex int, chunkWaitGroup *sync.WaitGroup) {
defer c.recoverInternalError(chunkWaitGroup, runtime.SourceIndex)
chunk := &chunks[chunkIndex]
timer := c.timer.Fork()
if timer != nil {
timeName := fmt.Sprintf("Generate chunk %q", path.Clean(config.TemplateToString(chunk.finalTemplate)))
timer.Begin(timeName)
defer c.timer.Join(timer)
defer timer.End(timeName)
}
chunkRepr := chunk.chunkRepr.(*chunkReprJS)
compileResults := make([]compileResultJS, 0, len(chunkRepr.partsInChunkInOrder))
runtimeMembers := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr).AST.ModuleScope.Members
toCommonJSRef := js_ast.FollowSymbols(c.graph.Symbols, runtimeMembers["__toCommonJS"].Ref)
toESMRef := js_ast.FollowSymbols(c.graph.Symbols, runtimeMembers["__toESM"].Ref)
runtimeRequireRef := js_ast.FollowSymbols(c.graph.Symbols, runtimeMembers["__require"].Ref)
r := c.renameSymbolsInChunk(chunk, chunkRepr.filesInChunkInOrder, timer)
dataForSourceMaps := c.dataForSourceMaps()
// Note: This contains placeholders instead of what the placeholders are
// substituted with. That should be fine though because this should only
// ever be used for figuring out how many "../" to add to a relative path
// from a chunk whose final path hasn't been calculated yet to a chunk
// whose final path has already been calculated. That and placeholders are
// never substituted with something containing a "/" so substitution should
// never change the "../" count.
chunkAbsDir := c.fs.Dir(c.fs.Join(c.options.AbsOutputDir, config.TemplateToString(chunk.finalTemplate)))
// Generate JavaScript for each file in parallel
timer.Begin("Print JavaScript files")
waitGroup := sync.WaitGroup{}
for _, partRange := range chunkRepr.partsInChunkInOrder {
// Skip the runtime in test output
if partRange.sourceIndex == runtime.SourceIndex && c.options.OmitRuntimeForTests {
continue
}
// Create a goroutine for this file
compileResults = append(compileResults, compileResultJS{})
compileResult := &compileResults[len(compileResults)-1]
waitGroup.Add(1)
go c.generateCodeForFileInChunkJS(
r,
&waitGroup,
partRange,
chunk.entryBits,
chunkAbsDir,
toCommonJSRef,
toESMRef,
runtimeRequireRef,
compileResult,
dataForSourceMaps,
)
}
// Also generate the cross-chunk binding code
var crossChunkPrefix []byte
var crossChunkSuffix []byte
{
// Indent the file if everything is wrapped in an IIFE
indent := 0
if c.options.OutputFormat == config.FormatIIFE {
indent++
}
printOptions := js_printer.Options{
Indent: indent,
OutputFormat: c.options.OutputFormat,
RemoveWhitespace: c.options.RemoveWhitespace,
MangleSyntax: c.options.MangleSyntax,
}
crossChunkImportRecords := make([]ast.ImportRecord, len(chunk.crossChunkImports))
for i, chunkImport := range chunk.crossChunkImports {
crossChunkImportRecords[i] = ast.ImportRecord{
Kind: chunkImport.importKind,
Path: logger.Path{Text: chunks[chunkImport.chunkIndex].uniqueKey},
}
}
crossChunkPrefix = js_printer.Print(js_ast.AST{
ImportRecords: crossChunkImportRecords,
Parts: []js_ast.Part{{Stmts: chunkRepr.crossChunkPrefixStmts}},
}, c.graph.Symbols, r, printOptions).JS
crossChunkSuffix = js_printer.Print(js_ast.AST{
Parts: []js_ast.Part{{Stmts: chunkRepr.crossChunkSuffixStmts}},
}, c.graph.Symbols, r, printOptions).JS
}
// Generate the exports for the entry point, if there are any
var entryPointTail compileResultJS
if chunk.isEntryPoint {
entryPointTail = c.generateEntryPointTailJS(
r,
toCommonJSRef,
toESMRef,
chunk.sourceIndex,
)
}
waitGroup.Wait()
timer.End("Print JavaScript files")
timer.Begin("Join JavaScript files")
j := helpers.Joiner{}
prevOffset := sourcemap.LineColumnOffset{}
// Optionally strip whitespace
indent := ""
space := " "
newline := "\n"
if c.options.RemoveWhitespace {
space = ""
newline = ""
}
newlineBeforeComment := false
isExecutable := false
if chunk.isEntryPoint {
repr := c.graph.Files[chunk.sourceIndex].InputFile.Repr.(*graph.JSRepr)
// Start with the hashbang if there is one
if repr.AST.Hashbang != "" {
hashbang := repr.AST.Hashbang + "\n"
prevOffset.AdvanceString(hashbang)
j.AddString(hashbang)
newlineBeforeComment = true
isExecutable = true
}
// Add the top-level directive if present
if repr.AST.Directive != "" {
quoted := string(js_printer.QuoteForJSON(repr.AST.Directive, c.options.ASCIIOnly)) + ";" + newline
prevOffset.AdvanceString(quoted)
j.AddString(quoted)
newlineBeforeComment = true
}
}
if len(c.options.JSBanner) > 0 {
prevOffset.AdvanceString(c.options.JSBanner)
prevOffset.AdvanceString("\n")
j.AddString(c.options.JSBanner)
j.AddString("\n")
}
// Optionally wrap with an IIFE
if c.options.OutputFormat == config.FormatIIFE {
var text string
indent = " "
if len(c.options.GlobalName) > 0 {
text = c.generateGlobalNamePrefix()
}
if c.options.UnsupportedJSFeatures.Has(compat.Arrow) {
text += "(function()" + space + "{" + newline
} else {
text += "(()" + space + "=>" + space + "{" + newline
}
prevOffset.AdvanceString(text)
j.AddString(text)
newlineBeforeComment = false
}
// Put the cross-chunk prefix inside the IIFE
if len(crossChunkPrefix) > 0 {
newlineBeforeComment = true
prevOffset.AdvanceBytes(crossChunkPrefix)
j.AddBytes(crossChunkPrefix)
}
// Start the metadata
jMeta := helpers.Joiner{}
if c.options.NeedsMetafile {
// Print imports
isFirstMeta := true
jMeta.AddString("{\n \"imports\": [")
for _, chunkImport := range chunk.crossChunkImports {
if isFirstMeta {
isFirstMeta = false
} else {
jMeta.AddString(",")
}
jMeta.AddString(fmt.Sprintf("\n {\n \"path\": %s,\n \"kind\": %s\n }",
js_printer.QuoteForJSON(c.res.PrettyPath(logger.Path{Text: chunks[chunkImport.chunkIndex].uniqueKey, Namespace: "file"}), c.options.ASCIIOnly),
js_printer.QuoteForJSON(chunkImport.importKind.StringForMetafile(), c.options.ASCIIOnly)))
}
if !isFirstMeta {
jMeta.AddString("\n ")
}
// Print exports
jMeta.AddString("],\n \"exports\": [")
var aliases []string
if c.options.OutputFormat.KeepES6ImportExportSyntax() {
if chunk.isEntryPoint {
if fileRepr := c.graph.Files[chunk.sourceIndex].InputFile.Repr.(*graph.JSRepr); fileRepr.Meta.Wrap == graph.WrapCJS {
aliases = []string{"default"}
} else {
resolvedExports := fileRepr.Meta.ResolvedExports
aliases = make([]string, 0, len(resolvedExports))
for alias := range resolvedExports {
aliases = append(aliases, alias)
}
}
} else {
aliases = make([]string, 0, len(chunkRepr.exportsToOtherChunks))
for _, alias := range chunkRepr.exportsToOtherChunks {
aliases = append(aliases, alias)
}
}
}
isFirstMeta = true
sort.Strings(aliases) // Sort for determinism
for _, alias := range aliases {
if isFirstMeta {
isFirstMeta = false
} else {
jMeta.AddString(",")
}
jMeta.AddString(fmt.Sprintf("\n %s",
js_printer.QuoteForJSON(alias, c.options.ASCIIOnly)))
}
if !isFirstMeta {
jMeta.AddString("\n ")
}
if chunk.isEntryPoint {
entryPoint := c.graph.Files[chunk.sourceIndex].InputFile.Source.PrettyPath
jMeta.AddString(fmt.Sprintf("],\n \"entryPoint\": %s,\n \"inputs\": {", js_printer.QuoteForJSON(entryPoint, c.options.ASCIIOnly)))
} else {
jMeta.AddString("],\n \"inputs\": {")
}
}
// Concatenate the generated JavaScript chunks together
var compileResultsForSourceMap []compileResultForSourceMap
var legalCommentList []string
var metaOrder []uint32
var metaByteCount map[string]int
legalCommentSet := make(map[string]bool)
prevFileNameComment := uint32(0)
if c.options.NeedsMetafile {
metaOrder = make([]uint32, 0, len(compileResults))
metaByteCount = make(map[string]int, len(compileResults))
}
for _, compileResult := range compileResults {
isRuntime := compileResult.sourceIndex == runtime.SourceIndex
for text := range compileResult.ExtractedLegalComments {
if !legalCommentSet[text] {
legalCommentSet[text] = true
legalCommentList = append(legalCommentList, text)
}
}
// Add a comment with the file path before the file contents
if c.options.Mode == config.ModeBundle && !c.options.RemoveWhitespace &&
prevFileNameComment != compileResult.sourceIndex && len(compileResult.JS) > 0 {
if newlineBeforeComment {
prevOffset.AdvanceString("\n")
j.AddString("\n")
}
path := c.graph.Files[compileResult.sourceIndex].InputFile.Source.PrettyPath
// Make sure newlines in the path can't cause a syntax error. This does
// not minimize allocations because it's expected that this case never
// comes up in practice.
path = strings.ReplaceAll(path, "\r", "\\r")
path = strings.ReplaceAll(path, "\n", "\\n")
path = strings.ReplaceAll(path, "\u2028", "\\u2028")
path = strings.ReplaceAll(path, "\u2029", "\\u2029")
text := fmt.Sprintf("%s// %s\n", indent, path)
prevOffset.AdvanceString(text)
j.AddString(text)
prevFileNameComment = compileResult.sourceIndex
}
// Don't include the runtime in source maps
if isRuntime {
prevOffset.AdvanceString(string(compileResult.JS))
j.AddBytes(compileResult.JS)
} else {
// Save the offset to the start of the stored JavaScript
compileResult.generatedOffset = prevOffset
j.AddBytes(compileResult.JS)
// Ignore empty source map chunks
if compileResult.SourceMapChunk.ShouldIgnore {
prevOffset.AdvanceBytes(compileResult.JS)
} else {
prevOffset = sourcemap.LineColumnOffset{}
// Include this file in the source map
if c.options.SourceMap != config.SourceMapNone {
compileResultsForSourceMap = append(compileResultsForSourceMap, compileResultForSourceMap{
sourceMapChunk: compileResult.SourceMapChunk,
generatedOffset: compileResult.generatedOffset,
sourceIndex: compileResult.sourceIndex,
})
}
}
// Include this file in the metadata
if c.options.NeedsMetafile {
// Accumulate file sizes since a given file may be split into multiple parts
path := c.graph.Files[compileResult.sourceIndex].InputFile.Source.PrettyPath
if count, ok := metaByteCount[path]; ok {
metaByteCount[path] = count + len(compileResult.JS)
} else {
metaOrder = append(metaOrder, compileResult.sourceIndex)
metaByteCount[path] = len(compileResult.JS)
}
}
}
// Put a newline before the next file path comment
if len(compileResult.JS) > 0 {
newlineBeforeComment = true
}
}
// Stick the entry point tail at the end of the file. Deliberately don't
// include any source mapping information for this because it's automatically
// generated and doesn't correspond to a location in the input file.
j.AddBytes(entryPointTail.JS)
// Put the cross-chunk suffix inside the IIFE
if len(crossChunkSuffix) > 0 {
if newlineBeforeComment {
j.AddString(newline)
}
j.AddBytes(crossChunkSuffix)
}
// Optionally wrap with an IIFE
if c.options.OutputFormat == config.FormatIIFE {
j.AddString("})();" + newline)
}
// Make sure the file ends with a newline
j.EnsureNewlineAtEnd()
maybeAppendLegalComments(c.options.LegalComments, legalCommentList, chunk, &j, "/script")
if len(c.options.JSFooter) > 0 {
j.AddString(c.options.JSFooter)
j.AddString("\n")
}
// The JavaScript contents are done now that the source map comment is in
chunk.intermediateOutput = c.breakOutputIntoPieces(j, uint32(len(chunks)))
timer.End("Join JavaScript files")
if c.options.SourceMap != config.SourceMapNone {
timer.Begin("Generate source map")
canHaveShifts := chunk.intermediateOutput.pieces != nil
chunk.outputSourceMap = c.generateSourceMapForChunk(compileResultsForSourceMap, chunkAbsDir, dataForSourceMaps, canHaveShifts)
timer.End("Generate source map")
}
// End the metadata lazily. The final output size is not known until the
// final import paths are substituted into the output pieces generated below.
if c.options.NeedsMetafile {
chunk.jsonMetadataChunkCallback = func(finalOutputSize int) helpers.Joiner {
isFirstMeta := true
for _, sourceIndex := range metaOrder {
if isFirstMeta {
isFirstMeta = false
} else {
jMeta.AddString(",")
}
path := c.graph.Files[sourceIndex].InputFile.Source.PrettyPath
extra := c.generateExtraDataForFileJS(sourceIndex)
jMeta.AddString(fmt.Sprintf("\n %s: {\n \"bytesInOutput\": %d\n %s}",
js_printer.QuoteForJSON(path, c.options.ASCIIOnly), metaByteCount[path], extra))
}
if !isFirstMeta {
jMeta.AddString("\n ")
}
jMeta.AddString(fmt.Sprintf("},\n \"bytes\": %d\n }", finalOutputSize))
return jMeta
}
}
c.generateIsolatedHashInParallel(chunk)
chunk.isExecutable = isExecutable
chunkWaitGroup.Done()
}
func (c *linkerContext) generateGlobalNamePrefix() string {
var text string
prefix := c.options.GlobalName[0]
space := " "
join := ";\n"
if c.options.RemoveWhitespace {
space = ""
join = ";"
}
if js_printer.CanEscapeIdentifier(prefix, c.options.UnsupportedJSFeatures, c.options.ASCIIOnly) {
if c.options.ASCIIOnly {
prefix = string(js_printer.QuoteIdentifier(nil, prefix, c.options.UnsupportedJSFeatures))
}
text = fmt.Sprintf("var %s%s=%s", prefix, space, space)
} else {
prefix = fmt.Sprintf("this[%s]", js_printer.QuoteForJSON(prefix, c.options.ASCIIOnly))
text = fmt.Sprintf("%s%s=%s", prefix, space, space)
}
for _, name := range c.options.GlobalName[1:] {
oldPrefix := prefix
if js_printer.CanEscapeIdentifier(name, c.options.UnsupportedJSFeatures, c.options.ASCIIOnly) {
if c.options.ASCIIOnly {
name = string(js_printer.QuoteIdentifier(nil, name, c.options.UnsupportedJSFeatures))
}
prefix = fmt.Sprintf("%s.%s", prefix, name)
} else {
prefix = fmt.Sprintf("%s[%s]", prefix, js_printer.QuoteForJSON(name, c.options.ASCIIOnly))
}
text += fmt.Sprintf("%s%s||%s{}%s%s%s=%s", oldPrefix, space, space, join, prefix, space, space)
}
return text
}
type compileResultCSS struct {
css_printer.PrintResult
sourceIndex uint32
// This is the line and column offset since the previous CSS string
// or the start of the file if this is the first CSS string.
generatedOffset sourcemap.LineColumnOffset
hasCharset bool
}
func (c *linkerContext) generateChunkCSS(chunks []chunkInfo, chunkIndex int, chunkWaitGroup *sync.WaitGroup) {
defer c.recoverInternalError(chunkWaitGroup, runtime.SourceIndex)
chunk := &chunks[chunkIndex]
timer := c.timer.Fork()
if timer != nil {
timeName := fmt.Sprintf("Generate chunk %q", path.Clean(config.TemplateToString(chunk.finalTemplate)))
timer.Begin(timeName)
defer c.timer.Join(timer)
defer timer.End(timeName)
}
chunkRepr := chunk.chunkRepr.(*chunkReprCSS)
compileResults := make([]compileResultCSS, len(chunkRepr.filesInChunkInOrder))
dataForSourceMaps := c.dataForSourceMaps()
// Note: This contains placeholders instead of what the placeholders are
// substituted with. That should be fine though because this should only
// ever be used for figuring out how many "../" to add to a relative path
// from a chunk whose final path hasn't been calculated yet to a chunk
// whose final path has already been calculated. That and placeholders are
// never substituted with something containing a "/" so substitution should
// never change the "../" count.
chunkAbsDir := c.fs.Dir(c.fs.Join(c.options.AbsOutputDir, config.TemplateToString(chunk.finalTemplate)))
// Generate CSS for each file in parallel
timer.Begin("Print CSS files")
waitGroup := sync.WaitGroup{}
for i, sourceIndex := range chunkRepr.filesInChunkInOrder {
// Create a goroutine for this file
waitGroup.Add(1)
go func(sourceIndex uint32, compileResult *compileResultCSS) {
defer c.recoverInternalError(&waitGroup, sourceIndex)
file := &c.graph.Files[sourceIndex]
ast := file.InputFile.Repr.(*graph.CSSRepr).AST
// Filter out "@charset" and "@import" rules
rules := make([]css_ast.Rule, 0, len(ast.Rules))
hasCharset := false
for _, rule := range ast.Rules {
switch rule.Data.(type) {
case *css_ast.RAtCharset:
hasCharset = true
continue
case *css_ast.RAtImport:
continue
}
rules = append(rules, rule)
}
ast.Rules = rules
// Only generate a source map if needed
var addSourceMappings bool
var inputSourceMap *sourcemap.SourceMap
var lineOffsetTables []sourcemap.LineOffsetTable
if file.InputFile.Loader.CanHaveSourceMap() && c.options.SourceMap != config.SourceMapNone {
addSourceMappings = true
inputSourceMap = file.InputFile.InputSourceMap
lineOffsetTables = dataForSourceMaps[sourceIndex].lineOffsetTables
}
cssOptions := css_printer.Options{
RemoveWhitespace: c.options.RemoveWhitespace,
ASCIIOnly: c.options.ASCIIOnly,
LegalComments: c.options.LegalComments,
AddSourceMappings: addSourceMappings,
InputSourceMap: inputSourceMap,
LineOffsetTables: lineOffsetTables,
}
*compileResult = compileResultCSS{
PrintResult: css_printer.Print(ast, cssOptions),
sourceIndex: sourceIndex,
hasCharset: hasCharset,
}
waitGroup.Done()
}(sourceIndex, &compileResults[i])
}
waitGroup.Wait()
timer.End("Print CSS files")
timer.Begin("Join CSS files")
j := helpers.Joiner{}
prevOffset := sourcemap.LineColumnOffset{}
newlineBeforeComment := false
if len(c.options.CSSBanner) > 0 {
prevOffset.AdvanceString(c.options.CSSBanner)
j.AddString(c.options.CSSBanner)
prevOffset.AdvanceString("\n")
j.AddString("\n")
}
// Generate any prefix rules now
{
tree := css_ast.AST{}
// "@charset" is the only thing that comes before "@import"
for _, compileResult := range compileResults {
if compileResult.hasCharset {
tree.Rules = append(tree.Rules, css_ast.Rule{Data: &css_ast.RAtCharset{Encoding: "UTF-8"}})
break
}
}
// Insert all external "@import" rules at the front. In CSS, all "@import"
// rules must come first or the browser will just ignore them.
for _, external := range chunkRepr.externalImportsInOrder {
var conditions []css_ast.Token
conditions, tree.ImportRecords = css_ast.CloneTokensWithImportRecords(
external.conditions, external.conditionImportRecords, conditions, tree.ImportRecords)
tree.Rules = append(tree.Rules, css_ast.Rule{Data: &css_ast.RAtImport{
ImportRecordIndex: uint32(len(tree.ImportRecords)),
ImportConditions: conditions,
}})
tree.ImportRecords = append(tree.ImportRecords, ast.ImportRecord{
Kind: ast.ImportAt,
Path: external.path,
})
}
if len(tree.Rules) > 0 {
result := css_printer.Print(tree, css_printer.Options{
RemoveWhitespace: c.options.RemoveWhitespace,
ASCIIOnly: c.options.ASCIIOnly,
})
if len(result.CSS) > 0 {
prevOffset.AdvanceBytes(result.CSS)
j.AddBytes(result.CSS)
newlineBeforeComment = true
}
}
}
// Start the metadata
jMeta := helpers.Joiner{}
if c.options.NeedsMetafile {
isFirstMeta := true
jMeta.AddString("{\n \"imports\": [")
for _, chunkImport := range chunk.crossChunkImports {
if isFirstMeta {
isFirstMeta = false
} else {
jMeta.AddString(",")
}
jMeta.AddString(fmt.Sprintf("\n {\n \"path\": %s,\n \"kind\": %s\n }",
js_printer.QuoteForJSON(c.res.PrettyPath(logger.Path{Text: chunks[chunkImport.chunkIndex].uniqueKey, Namespace: "file"}), c.options.ASCIIOnly),
js_printer.QuoteForJSON(chunkImport.importKind.StringForMetafile(), c.options.ASCIIOnly)))
}
if !isFirstMeta {
jMeta.AddString("\n ")
}
if chunk.isEntryPoint {
file := &c.graph.Files[chunk.sourceIndex]
// Do not generate "entryPoint" for CSS files that are the result of
// importing CSS into JavaScript. We want this to be a 1:1 relationship
// and there is already an output file for the JavaScript entry point.
if _, ok := file.InputFile.Repr.(*graph.CSSRepr); ok {
jMeta.AddString(fmt.Sprintf("],\n \"entryPoint\": %s,\n \"inputs\": {",
js_printer.QuoteForJSON(file.InputFile.Source.PrettyPath, c.options.ASCIIOnly)))
} else {
jMeta.AddString("],\n \"inputs\": {")
}
} else {
jMeta.AddString("],\n \"inputs\": {")
}
}
isFirstMeta := true
// Concatenate the generated CSS chunks together
var compileResultsForSourceMap []compileResultForSourceMap
var legalCommentList []string
legalCommentSet := make(map[string]bool)
for _, compileResult := range compileResults {
for text := range compileResult.ExtractedLegalComments {
if !legalCommentSet[text] {
legalCommentSet[text] = true
legalCommentList = append(legalCommentList, text)
}
}
if c.options.Mode == config.ModeBundle && !c.options.RemoveWhitespace {
var newline string
if newlineBeforeComment {
newline = "\n"
}
comment := fmt.Sprintf("%s/* %s */\n", newline, c.graph.Files[compileResult.sourceIndex].InputFile.Source.PrettyPath)
prevOffset.AdvanceString(comment)
j.AddString(comment)
}
if len(compileResult.CSS) > 0 {
newlineBeforeComment = true
}
// Save the offset to the start of the stored JavaScript
compileResult.generatedOffset = prevOffset
j.AddBytes(compileResult.CSS)
// Ignore empty source map chunks
if compileResult.SourceMapChunk.ShouldIgnore {
prevOffset.AdvanceBytes(compileResult.CSS)
} else {
prevOffset = sourcemap.LineColumnOffset{}
// Include this file in the source map
if c.options.SourceMap != config.SourceMapNone {
compileResultsForSourceMap = append(compileResultsForSourceMap, compileResultForSourceMap{
sourceMapChunk: compileResult.SourceMapChunk,
generatedOffset: compileResult.generatedOffset,
sourceIndex: compileResult.sourceIndex,
})
}
}
// Include this file in the metadata
if c.options.NeedsMetafile {
if isFirstMeta {
isFirstMeta = false
} else {
jMeta.AddString(",")
}
jMeta.AddString(fmt.Sprintf("\n %s: {\n \"bytesInOutput\": %d\n }",
js_printer.QuoteForJSON(c.graph.Files[compileResult.sourceIndex].InputFile.Source.PrettyPath, c.options.ASCIIOnly),
len(compileResult.CSS)))
}
}
// Make sure the file ends with a newline
j.EnsureNewlineAtEnd()
maybeAppendLegalComments(c.options.LegalComments, legalCommentList, chunk, &j, "/style")
if len(c.options.CSSFooter) > 0 {
j.AddString(c.options.CSSFooter)
j.AddString("\n")
}
// The CSS contents are done now that the source map comment is in
chunk.intermediateOutput = c.breakOutputIntoPieces(j, uint32(len(chunks)))
timer.End("Join CSS files")
if c.options.SourceMap != config.SourceMapNone {
timer.Begin("Generate source map")
canHaveShifts := chunk.intermediateOutput.pieces != nil
chunk.outputSourceMap = c.generateSourceMapForChunk(compileResultsForSourceMap, chunkAbsDir, dataForSourceMaps, canHaveShifts)
timer.End("Generate source map")
}
// End the metadata lazily. The final output size is not known until the
// final import paths are substituted into the output pieces generated below.
if c.options.NeedsMetafile {
chunk.jsonMetadataChunkCallback = func(finalOutputSize int) helpers.Joiner {
if !isFirstMeta {
jMeta.AddString("\n ")
}
jMeta.AddString(fmt.Sprintf("},\n \"bytes\": %d\n }", finalOutputSize))
return jMeta
}
}
c.generateIsolatedHashInParallel(chunk)
chunkWaitGroup.Done()
}
// Add all unique legal comments to the end of the file. These are
// deduplicated because some projects have thousands of files with the same
// comment. The comment must be preserved in the output for legal reasons but
// at the same time we want to generate a small bundle when minifying.
func maybeAppendLegalComments(
legalComments config.LegalComments,
legalCommentList []string,
chunk *chunkInfo,
j *helpers.Joiner,
slashTag string,
) {
if len(legalCommentList) > 0 {
sort.Strings(legalCommentList)
switch legalComments {
case config.LegalCommentsEndOfFile:
for _, text := range legalCommentList {
j.AddString(helpers.EscapeClosingTag(text, slashTag))
j.AddString("\n")
}
case config.LegalCommentsLinkedWithComment,
config.LegalCommentsExternalWithoutComment:
jComments := helpers.Joiner{}
for _, text := range legalCommentList {
jComments.AddString(text)
jComments.AddString("\n")
}
chunk.externalLegalComments = jComments.Done()
}
}
}
func appendIsolatedHashesForImportedChunks(
hash hash.Hash,
chunks []chunkInfo,
chunkIndex uint32,
visited []uint32,
visitedKey uint32,
) {
// Only visit each chunk at most once. This is important because there may be
// cycles in the chunk import graph. If there's a cycle, we want to include
// the hash of every chunk involved in the cycle (along with all of their
// dependencies). This depth-first traversal will naturally do that.
if visited[chunkIndex] == visitedKey {
return
}
visited[chunkIndex] = visitedKey
chunk := &chunks[chunkIndex]
// Visit the other chunks that this chunk imports before visiting this chunk
for _, chunkImport := range chunk.crossChunkImports {
appendIsolatedHashesForImportedChunks(hash, chunks, chunkImport.chunkIndex, visited, visitedKey)
}
// Mix in the hash for this chunk
hash.Write(chunk.waitForIsolatedHash())
}
func (c *linkerContext) breakOutputIntoPieces(j helpers.Joiner, chunkCount uint32) intermediateOutput {
// Optimization: If there can be no substitutions, just reuse the initial
// joiner that was used when generating the intermediate chunk output
// instead of creating another one and copying the whole file into it.
if !j.Contains(c.uniqueKeyPrefix, c.uniqueKeyPrefixBytes) {
return intermediateOutput{joiner: j}
}
var pieces []outputPiece
output := j.Done()
prefix := c.uniqueKeyPrefixBytes
for {
// Scan for the next piece boundary
boundary := bytes.Index(output, prefix)
// Try to parse the piece boundary
var kind outputPieceIndexKind
var index uint32
if boundary != -1 {
if start := boundary + len(prefix); start+9 > len(output) {
boundary = -1
} else {
switch output[start] {
case 'A':
kind = outputPieceAssetIndex
case 'C':
kind = outputPieceChunkIndex
}
for j := 1; j < 9; j++ {
c := output[start+j]
if c < '0' || c > '9' {
boundary = -1
break
}
index = index*10 + uint32(c) - '0'
}
}
}
// Validate the boundary
switch kind {
case outputPieceAssetIndex:
if index >= uint32(len(c.graph.Files)) {
boundary = -1
}
case outputPieceChunkIndex:
if index >= chunkCount {
boundary = -1
}
default:
boundary = -1
}
// If we're at the end, generate one final piece
if boundary == -1 {
pieces = append(pieces, outputPiece{
data: output,
})
break
}
// Otherwise, generate an interior piece and continue
pieces = append(pieces, outputPiece{
data: output[:boundary],
index: index,
kind: kind,
})
output = output[boundary+len(prefix)+9:]
}
return intermediateOutput{pieces: pieces}
}
func (c *linkerContext) generateIsolatedHashInParallel(chunk *chunkInfo) {
// Compute the hash in parallel. This is a speedup when it turns out the hash
// isn't needed (well, as long as there are threads to spare).
channel := make(chan []byte, 1)
chunk.waitForIsolatedHash = func() []byte {
data := <-channel
channel <- data
return data
}
go c.generateIsolatedHash(chunk, channel)
}
func (c *linkerContext) generateIsolatedHash(chunk *chunkInfo, channel chan []byte) {
hash := xxhash.New()
// Mix the file names and part ranges of all of the files in this chunk into
// the hash. Objects that appear identical but that live in separate files or
// that live in separate parts in the same file must not be merged. This only
// needs to be done for JavaScript files, not CSS files.
if chunkRepr, ok := chunk.chunkRepr.(*chunkReprJS); ok {
for _, partRange := range chunkRepr.partsInChunkInOrder {
var filePath string
file := &c.graph.Files[partRange.sourceIndex]
if file.InputFile.Source.KeyPath.Namespace == "file" {
// Use the pretty path as the file name since it should be platform-
// independent (relative paths and the "/" path separator)
filePath = file.InputFile.Source.PrettyPath
} else {
// If this isn't in the "file" namespace, just use the full path text
// verbatim. This could be a source of cross-platform differences if
// plugins are storing platform-specific information in here, but then
// that problem isn't caused by esbuild itself.
filePath = file.InputFile.Source.KeyPath.Text
}
// Include the path namespace in the hash
hashWriteLengthPrefixed(hash, []byte(file.InputFile.Source.KeyPath.Namespace))
// Then include the file path
hashWriteLengthPrefixed(hash, []byte(filePath))
// Also write the part range. These numbers are deterministic and allocated
// per-file so this should be a well-behaved base for a hash.
hashWriteUint32(hash, partRange.partIndexBegin)
hashWriteUint32(hash, partRange.partIndexEnd)
}
}
// Hash the output path template as part of the content hash because we want
// any import to be considered different if the import's output path has changed.
for _, part := range chunk.finalTemplate {
hashWriteLengthPrefixed(hash, []byte(part.Data))
}
// Include the generated output content in the hash. This excludes the
// randomly-generated import paths (the unique keys) and only includes the
// data in the spans between them.
if chunk.intermediateOutput.pieces != nil {
for _, piece := range chunk.intermediateOutput.pieces {
hashWriteLengthPrefixed(hash, piece.data)
}
} else {
bytes := chunk.intermediateOutput.joiner.Done()
hashWriteLengthPrefixed(hash, bytes)
}
// Also include the source map data in the hash. The source map is named the
// same name as the chunk name for ease of discovery. So we want the hash to
// change if the source map data changes even if the chunk data doesn't change.
// Otherwise the output path for the source map wouldn't change and the source
// map wouldn't end up being updated.
//
// Note that this means the contents of all input files are included in the
// hash because of "sourcesContent", so changing a comment in an input file
// can now change the hash of the output file. This only happens when you
// have source maps enabled (and "sourcesContent", which is on by default).
//
// The generated positions in the mappings here are in the output content
// *before* the final paths have been substituted. This may seem weird.
// However, I think this shouldn't cause issues because a) the unique key
// values are all always the same length so the offsets are deterministic
// and b) the final paths will be folded into the final hash later.
hashWriteLengthPrefixed(hash, chunk.outputSourceMap.Prefix)
hashWriteLengthPrefixed(hash, chunk.outputSourceMap.Mappings)
hashWriteLengthPrefixed(hash, chunk.outputSourceMap.Suffix)
// Store the hash so far. All other chunks that import this chunk will mix
// this hash into their final hash to ensure that the import path changes
// if this chunk (or any dependencies of this chunk) is changed.
channel <- hash.Sum(nil)
}
func hashWriteUint32(hash hash.Hash, value uint32) {
var lengthBytes [4]byte
binary.LittleEndian.PutUint32(lengthBytes[:], value)
hash.Write(lengthBytes[:])
}
// Hash the data in length-prefixed form because boundary locations are
// important. We don't want "a" + "bc" to hash the same as "ab" + "c".
func hashWriteLengthPrefixed(hash hash.Hash, bytes []byte) {
hashWriteUint32(hash, uint32(len(bytes)))
hash.Write(bytes)
}
func preventBindingsFromBeingRenamed(binding js_ast.Binding, symbols js_ast.SymbolMap) {
switch b := binding.Data.(type) {
case *js_ast.BMissing:
case *js_ast.BIdentifier:
symbols.Get(b.Ref).MustNotBeRenamed = true
case *js_ast.BArray:
for _, i := range b.Items {
preventBindingsFromBeingRenamed(i.Binding, symbols)
}
case *js_ast.BObject:
for _, p := range b.Properties {
preventBindingsFromBeingRenamed(p.Value, symbols)
}
default:
panic(fmt.Sprintf("Unexpected binding of type %T", binding.Data))
}
}
// Marking a symbol as unbound prevents it from being renamed or minified.
// This is only used when a module is compiled independently. We use a very
// different way of handling exports and renaming/minifying when bundling.
func (c *linkerContext) preventExportsFromBeingRenamed(sourceIndex uint32) {
repr, ok := c.graph.Files[sourceIndex].InputFile.Repr.(*graph.JSRepr)
if !ok {
return
}
hasImportOrExport := false
for _, part := range repr.AST.Parts {
for _, stmt := range part.Stmts {
switch s := stmt.Data.(type) {
case *js_ast.SImport:
// Ignore imports from the internal runtime code. These are generated
// automatically and aren't part of the original source code. We
// shouldn't consider the file a module if the only ES6 import or
// export is the automatically generated one.
record := &repr.AST.ImportRecords[s.ImportRecordIndex]
if record.SourceIndex.IsValid() && record.SourceIndex.GetIndex() == runtime.SourceIndex {
continue
}
hasImportOrExport = true
case *js_ast.SLocal:
if s.IsExport {
for _, decl := range s.Decls {
preventBindingsFromBeingRenamed(decl.Binding, c.graph.Symbols)
}
hasImportOrExport = true
}
case *js_ast.SFunction:
if s.IsExport {
c.graph.Symbols.Get(s.Fn.Name.Ref).Kind = js_ast.SymbolUnbound
hasImportOrExport = true
}
case *js_ast.SClass:
if s.IsExport {
c.graph.Symbols.Get(s.Class.Name.Ref).Kind = js_ast.SymbolUnbound
hasImportOrExport = true
}
case *js_ast.SExportClause, *js_ast.SExportDefault, *js_ast.SExportStar:
hasImportOrExport = true
case *js_ast.SExportFrom:
hasImportOrExport = true
}
}
}
// Heuristic: If this module has top-level import or export statements, we
// consider this an ES6 module and only preserve the names of the exported
// symbols. Everything else is minified since the names are private.
//
// Otherwise, we consider this potentially a script-type file instead of an
// ES6 module. In that case, preserve the names of all top-level symbols
// since they are all potentially exported (e.g. if this is used in a
// <script> tag). All symbols in nested scopes are still minified.
if !hasImportOrExport {
for _, member := range repr.AST.ModuleScope.Members {
c.graph.Symbols.Get(member.Ref).MustNotBeRenamed = true
}
}
}
type compileResultForSourceMap struct {
sourceMapChunk sourcemap.Chunk
generatedOffset sourcemap.LineColumnOffset
sourceIndex uint32
}
func (c *linkerContext) generateSourceMapForChunk(
results []compileResultForSourceMap,
chunkAbsDir string,
dataForSourceMaps []dataForSourceMap,
canHaveShifts bool,
) (pieces sourcemap.SourceMapPieces) {
j := helpers.Joiner{}
j.AddString("{\n \"version\": 3")
// Only write out the sources for a given source index once
sourceIndexToSourcesIndex := make(map[uint32]int)
// Generate the "sources" and "sourcesContent" arrays
type item struct {
path logger.Path
prettyPath string
quotedContents []byte
}
items := make([]item, 0, len(results))
nextSourcesIndex := 0
for _, result := range results {
if _, ok := sourceIndexToSourcesIndex[result.sourceIndex]; ok {
continue
}
sourceIndexToSourcesIndex[result.sourceIndex] = nextSourcesIndex
file := &c.graph.Files[result.sourceIndex]
// Simple case: no nested source map
if file.InputFile.InputSourceMap == nil {
var quotedContents []byte
if !c.options.ExcludeSourcesContent {
quotedContents = dataForSourceMaps[result.sourceIndex].quotedContents[0]
}
items = append(items, item{
path: file.InputFile.Source.KeyPath,
prettyPath: file.InputFile.Source.PrettyPath,
quotedContents: quotedContents,
})
nextSourcesIndex++
continue
}
// Complex case: nested source map
sm := file.InputFile.InputSourceMap
for i, source := range sm.Sources {
path := logger.Path{
Namespace: file.InputFile.Source.KeyPath.Namespace,
Text: source,
}
// If this file is in the "file" namespace, change the relative path in
// the source map into an absolute path using the directory of this file
if path.Namespace == "file" {
path.Text = c.fs.Join(c.fs.Dir(file.InputFile.Source.KeyPath.Text), source)
}
var quotedContents []byte
if !c.options.ExcludeSourcesContent {
quotedContents = dataForSourceMaps[result.sourceIndex].quotedContents[i]
}
items = append(items, item{
path: path,
prettyPath: source,
quotedContents: quotedContents,
})
}
nextSourcesIndex += len(sm.Sources)
}
// Write the sources
j.AddString(",\n \"sources\": [")
for i, item := range items {
if i != 0 {
j.AddString(", ")
}
// Modify the absolute path to the original file to be relative to the
// directory that will contain the output file for this chunk
if item.path.Namespace == "file" {
if relPath, ok := c.fs.Rel(chunkAbsDir, item.path.Text); ok {
// Make sure to always use forward slashes, even on Windows
item.prettyPath = strings.ReplaceAll(relPath, "\\", "/")
}
}
j.AddBytes(js_printer.QuoteForJSON(item.prettyPath, c.options.ASCIIOnly))
}
j.AddString("]")
if c.options.SourceRoot != "" {
j.AddString(",\n \"sourceRoot\": ")
j.AddBytes(js_printer.QuoteForJSON(c.options.SourceRoot, c.options.ASCIIOnly))
}
// Write the sourcesContent
if !c.options.ExcludeSourcesContent {
j.AddString(",\n \"sourcesContent\": [")
for i, item := range items {
if i != 0 {
j.AddString(", ")
}
j.AddBytes(item.quotedContents)
}
j.AddString("]")
}
j.AddString(",\n \"mappings\": \"")
// Write the mappings
mappingsStart := j.Length()
prevEndState := sourcemap.SourceMapState{}
prevColumnOffset := 0
for _, result := range results {
chunk := result.sourceMapChunk
offset := result.generatedOffset
sourcesIndex := sourceIndexToSourcesIndex[result.sourceIndex]
// This should have already been checked earlier
if chunk.ShouldIgnore {
panic("Internal error")
}
// Because each file for the bundle is converted to a source map once,
// the source maps are shared between all entry points in the bundle.
// The easiest way of getting this to work is to have all source maps
// generate as if their source index is 0. We then adjust the source
// index per entry point by modifying the first source mapping. This
// is done by AppendSourceMapChunk() using the source index passed
// here.
startState := sourcemap.SourceMapState{
SourceIndex: sourcesIndex,
GeneratedLine: offset.Lines,
GeneratedColumn: offset.Columns,
}
if offset.Lines == 0 {
startState.GeneratedColumn += prevColumnOffset
}
// Append the precomputed source map chunk
sourcemap.AppendSourceMapChunk(&j, prevEndState, startState, chunk.Buffer)
// Generate the relative offset to start from next time
prevEndState = chunk.EndState
prevEndState.SourceIndex += sourcesIndex
prevColumnOffset = chunk.FinalGeneratedColumn
// If this was all one line, include the column offset from the start
if prevEndState.GeneratedLine == 0 {
prevEndState.GeneratedColumn += startState.GeneratedColumn
prevColumnOffset += startState.GeneratedColumn
}
}
mappingsEnd := j.Length()
// Finish the source map
j.AddString("\",\n \"names\": []\n}\n")
bytes := j.Done()
if !canHaveShifts {
// If there cannot be any shifts, then we can avoid doing extra work later
// on by preserving the source map as a single memory allocation throughout
// the pipeline. That way we won't need to reallocate it.
pieces.Prefix = bytes
} else {
// Otherwise if there can be shifts, then we need to split this into several
// slices so that the shifts in the mappings array can be processed. This is
// more expensive because everything will need to be recombined into a new
// memory allocation at the end.
pieces.Prefix = bytes[:mappingsStart]
pieces.Mappings = bytes[mappingsStart:mappingsEnd]
pieces.Suffix = bytes[mappingsEnd:]
}
return
}
// Recover from a panic by logging it as an internal error instead of crashing
func (c *linkerContext) recoverInternalError(waitGroup *sync.WaitGroup, sourceIndex uint32) {
if r := recover(); r != nil {
text := fmt.Sprintf("panic: %v", r)
if sourceIndex != runtime.SourceIndex {
text = fmt.Sprintf("%s (while printing %q)", text, c.graph.Files[sourceIndex].InputFile.Source.PrettyPath)
}
c.log.AddWithNotes(logger.Error, nil, logger.Range{}, text,
[]logger.MsgData{{Text: helpers.PrettyPrintedStack()}})
waitGroup.Done()
}
}