add --outbase option

cmd/esbuild/main.go

@@ -21,6 +21,7 @@ Options:
   --bundle              Bundle all dependencies into the output files
   --outfile=...         The output file (for one entry point)
   --outdir=...          The output directory (for multiple entry points)
+  --outbase=...         The base path used to determine entry point output paths (for multiple entry points)
   --sourcemap           Emit a source map
   --target=...          Environment target (e.g. es2017, chrome58, firefox57,
                         safari11, edge16, node10, default esnext)

internal/bundler/bundler.go

@@ -890,8 +890,13 @@ func (b *Bundle) Compile(log logger.Log, options config.Options) []OutputFile {
 		options.OutputFormat = config.FormatESModule
 	}
 
-	// Determine the lowest common ancestor of all entry points
-	lcaAbsPath := b.lowestCommonAncestorDirectory(options.CodeSplitting)
+	// Get the base path from the options or choose the lowest common ancestor of all entry points
+	var baseAbsPath string
+	if options.AbsOutputBase != "" {
+		baseAbsPath = options.AbsOutputBase
+	} else {
+		baseAbsPath = b.lowestCommonAncestorDirectory(options.CodeSplitting)
+	}
 
 	type linkGroup struct {
 		outputFiles    []OutputFile
@@ -901,7 +906,7 @@ func (b *Bundle) Compile(log logger.Log, options config.Options) []OutputFile {
 	var resultGroups []linkGroup
 	if options.CodeSplitting {
 		// If code splitting is enabled, link all entry points together
-		c := newLinkerContext(&options, log, b.fs, b.res, b.files, b.entryPoints, lcaAbsPath)
+		c := newLinkerContext(&options, log, b.fs, b.res, b.files, b.entryPoints, baseAbsPath)
 		resultGroups = []linkGroup{{
 			outputFiles:    c.link(),
 			reachableFiles: c.reachableFiles,
@@ -913,7 +918,7 @@ func (b *Bundle) Compile(log logger.Log, options config.Options) []OutputFile {
 		for i, entryPoint := range b.entryPoints {
 			waitGroup.Add(1)
 			go func(i int, entryPoint uint32) {
-				c := newLinkerContext(&options, log, b.fs, b.res, b.files, []uint32{entryPoint}, lcaAbsPath)
+				c := newLinkerContext(&options, log, b.fs, b.res, b.files, []uint32{entryPoint}, baseAbsPath)
 				resultGroups[i] = linkGroup{
 					outputFiles:    c.link(),
 					reachableFiles: c.reachableFiles,

internal/bundler/bundler_default_test.go

@@ -3169,6 +3169,25 @@ func TestInjectImportOrder(t *testing.T) {
 	})
 }
 
+func TestOutbase(t *testing.T) {
+	default_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/a/b/c.js": `
+				console.log('c')
+			`,
+			"/a/b/d.js": `
+				console.log('d')
+			`,
+		},
+		entryPaths: []string{"/a/b/c.js", "/a/b/d.js"},
+		options: config.Options{
+			Mode:          config.ModeBundle,
+			AbsOutputDir:  "/out",
+			AbsOutputBase: "/",
+		},
+	})
+}
+
 func TestAvoidTDZNoBundle(t *testing.T) {
 	default_suite.expectBundled(t, bundled{
 		files: map[string]string{

internal/bundler/linker.go

@@ -64,7 +64,7 @@ type linkerContext struct {
 	entryPoints []uint32
 	files       []file
 	hasErrors   bool
-	lcaAbsPath  string
+	baseAbsPath string
 
 	// We should avoid traversing all files in the bundle, because the linker
 	// should be able to run a linking operation on a large bundle where only
@@ -305,7 +305,7 @@ func newLinkerContext(
 	res resolver.Resolver,
 	files []file,
 	entryPoints []uint32,
-	lcaAbsPath string,
+	baseAbsPath string,
 ) linkerContext {
 	// Clone information about symbols and files so we don't mutate the input data
 	c := linkerContext{
@@ -317,7 +317,7 @@ func newLinkerContext(
 		files:          make([]file, len(files)),
 		symbols:        js_ast.NewSymbolMap(len(files)),
 		reachableFiles: findReachableFiles(files, entryPoints),
-		lcaAbsPath:     lcaAbsPath,
+		baseAbsPath:    baseAbsPath,
 	}
 
 	// Clone various things since we may mutate them later
@@ -2388,7 +2388,7 @@ func (c *linkerContext) computeChunks() []chunkInfo {
 			source := file.source
 			if source.KeyPath.Namespace != "file" {
 				baseName = source.IdentifierName
-			} else if relPath, ok := c.fs.Rel(c.lcaAbsPath, source.KeyPath.Text); ok {
+			} else if relPath, ok := c.fs.Rel(c.baseAbsPath, source.KeyPath.Text); ok {
 				relDir = c.fs.Dir(relPath)
 				baseName = c.fs.Base(relPath)
 			} else {

internal/bundler/snapshots/snapshots_default.txt

@@ -1370,6 +1370,16 @@ var require_demo_pkg = __commonJS((exports, module) => {
 const demo_pkg = __toModule(require_demo_pkg());
 console.log(demo_pkg.default());
 
+================================================================================
+TestOutbase
+---------- /out/a/b/c.js ----------
+// /a/b/c.js
+console.log("c");
+
+---------- /out/a/b/d.js ----------
+// /a/b/d.js
+console.log("d");
+
 ================================================================================
 TestOutputExtensionRemappingDir
 ---------- /out/entry.notjs ----------

internal/config/config.go

@@ -185,6 +185,7 @@ type Options struct {
 
 	AbsOutputFile     string
 	AbsOutputDir      string
+	AbsOutputBase     string
 	OutputExtensions  map[string]string
 	ModuleName        []string
 	TsConfigOverride  string

pkg/api/api.go

@@ -215,6 +215,7 @@ type BuildOptions struct {
 	Outfile           string
 	Metafile          string
 	Outdir            string
+	Outbase           string
 	Platform          Platform
 	Format            Format
 	External          []string

pkg/api/api_impl.go

@@ -445,6 +445,7 @@ func buildImpl(buildOpts BuildOptions) BuildResult {
 		OutputFormat:      validateFormat(buildOpts.Format),
 		AbsOutputFile:     validatePath(log, realFS, buildOpts.Outfile),
 		AbsOutputDir:      validatePath(log, realFS, buildOpts.Outdir),
+		AbsOutputBase:     validatePath(log, realFS, buildOpts.Outbase),
 		AbsMetadataFile:   validatePath(log, realFS, buildOpts.Metafile),
 		OutputExtensions:  validateOutputExtensions(log, buildOpts.OutExtensions),
 		ExtensionToLoader: validateLoaders(log, buildOpts.Loader),

pkg/cli/cli_impl.go

@@ -152,6 +152,9 @@ func parseOptionsImpl(osArgs []string, buildOpts *api.BuildOptions, transformOpt
 		case strings.HasPrefix(arg, "--outdir=") && buildOpts != nil:
 			buildOpts.Outdir = arg[len("--outdir="):]
 
+		case strings.HasPrefix(arg, "--outbase=") && buildOpts != nil:
+			buildOpts.Outbase = arg[len("--outbase="):]
+
 		case strings.HasPrefix(arg, "--tsconfig=") && buildOpts != nil:
 			buildOpts.Tsconfig = arg[len("--tsconfig="):]