New command structure. Add replace command.

build.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/evanw/esbuild/pkg/api"
+	"github.com/urfave/cli/v2"
+)
+
+func buildAction(ctx *cli.Context) error {
+	cfgPath := ctx.String("c")
+	os.Chdir(filepath.Dir(cfgPath))
+	opts := readCfg(cfgPath)
+
+	for _, o := range opts {
+		cp(o)
+
+		if ctx.Bool("p") {
+			o.ESBuild.MinifyIdentifiers = true
+			o.ESBuild.MinifySyntax = true
+			o.ESBuild.MinifyWhitespace = true
+			o.ESBuild.Sourcemap = api.SourceMapNone
+		}
+
+		api.Build(o.ESBuild)
+		replace(o)
+	}
+
+	return nil
+}