Add post build command and exclude the esbuild outdir in the watcher.

build.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 
 	"github.com/evanw/esbuild/pkg/api"
@@ -34,6 +36,19 @@ func buildAction(ctx *cli.Context) error {
 
 		api.Build(o.ESBuild.BuildOptions)
 		replace(o)
+
+		if ctx.Bool("p") && o.ProductionBuildOptions.CmdPostBuild != "" {
+			fmt.Printf("Executing post production build command `%s`\n", o.ProductionBuildOptions.CmdPostBuild)
+			cmd := exec.Command("sh", "-c", o.ProductionBuildOptions.CmdPostBuild)
+			cmd.Stdout = os.Stdout
+			cmd.Stderr = os.Stderr
+			err := cmd.Run()
+
+			if err != nil {
+				fmt.Printf("Failed to execute post production build command `%s`: %+v\n", o.ProductionBuildOptions.CmdPostBuild, err)
+				os.Exit(1)
+			}
+		}
 	}
 
 	return nil