add "--sources-content=false" (#624)

CHANGELOG.md

@@ -10,6 +10,10 @@
 
     If the working directory ended in `/`, the last path component would be incorrectly duplicated. This was the case when running esbuild with Yarn 2 (but not Yarn 1) and is problematic because some externally-facing directories reference the current working directory in plugins and in output files. The problem has now been fixed and the last path component is no longer duplicated in this case. This fix was contributed by [@remorses](https://github.com/remorses).
 
+* Add an option to omit `sourcesContent` from generated source maps ([#624](https://github.com/evanw/esbuild/issues/624))
+
+    You can now pass `--sources-content=false` to omit the `sourcesContent` field from generated source maps. The field embeds the original source code inline in the source map and is the largest part of the source map. This is useful if you don't need the original source code and would like a smaller source map (e.g. you only care about stack traces and don't need the source code for debugging).
+
 ## 0.8.26
 
 * Ensure the current working directory remains unique per `startService()` call

cmd/esbuild/main.go

@@ -75,6 +75,7 @@ var helpText = func(colors logger.Colors) string {
   --sourcefile=...          Set the source file for the source map (for stdin)
   --sourcemap=external      Do not link to the source map with a comment
   --sourcemap=inline        Emit the source map with an inline data URL
+  --sources-content=false   Omit "sourcesContent" in generated source maps
   --tree-shaking=...        Set to "ignore-annotations" to work with packages
                             that have incorrect tree-shaking annotations
   --tsconfig=...            Use this tsconfig.json file instead of other ones

internal/bundler/bundler.go

@@ -1487,28 +1487,30 @@ func (b *Bundle) computeDataForSourceMapsInParallel(options *config.Options, rea
 					result := &results[sourceIndex]
 					result.lineOffsetTables = js_printer.GenerateLineOffsetTables(f.source.Contents, repr.ast.ApproximateLineCount)
 					sm := f.sourceMap
-					if sm == nil {
-						// Simple case: no nested source map
-						result.quotedContents = [][]byte{js_printer.QuoteForJSON(f.source.Contents, options.ASCIIOnly)}
-					} else {
-						// Complex case: nested source map
-						result.quotedContents = make([][]byte, len(sm.Sources))
-						nullContents := []byte("null")
-						for i := range sm.Sources {
-							// Missing contents become a "null" literal
-							quotedContents := nullContents
-							if i < len(sm.SourcesContent) {
-								if value := sm.SourcesContent[i]; value.Quoted != "" {
-									if options.ASCIIOnly && !isASCIIOnly(value.Quoted) {
-										// Re-quote non-ASCII values if output is ASCII-only
-										quotedContents = js_printer.QuoteForJSON(js_lexer.UTF16ToString(value.Value), options.ASCIIOnly)
-									} else {
-										// Otherwise just use the value directly from the input file
-										quotedContents = []byte(value.Quoted)
+					if !options.ExcludeSourcesContent {
+						if sm == nil {
+							// Simple case: no nested source map
+							result.quotedContents = [][]byte{js_printer.QuoteForJSON(f.source.Contents, options.ASCIIOnly)}
+						} else {
+							// Complex case: nested source map
+							result.quotedContents = make([][]byte, len(sm.Sources))
+							nullContents := []byte("null")
+							for i := range sm.Sources {
+								// Missing contents become a "null" literal
+								quotedContents := nullContents
+								if i < len(sm.SourcesContent) {
+									if value := sm.SourcesContent[i]; value.Quoted != "" {
+										if options.ASCIIOnly && !isASCIIOnly(value.Quoted) {
+											// Re-quote non-ASCII values if output is ASCII-only
+											quotedContents = js_printer.QuoteForJSON(js_lexer.UTF16ToString(value.Value), options.ASCIIOnly)
+										} else {
+											// Otherwise just use the value directly from the input file
+											quotedContents = []byte(value.Quoted)
+										}
 									}
 								}
+								result.quotedContents[i] = quotedContents
 							}
-							result.quotedContents[i] = quotedContents
 						}
 					}
 					waitGroup.Done()

internal/bundler/linker.go

@@ -4266,10 +4266,14 @@ func (c *linkerContext) generateSourceMapForChunk(
 
 		// Simple case: no nested source map
 		if file.sourceMap == nil {
+			var quotedContents []byte
+			if !c.options.ExcludeSourcesContent {
+				quotedContents = dataForSourceMaps[result.sourceIndex].quotedContents[0]
+			}
 			items = append(items, item{
 				path:           file.source.KeyPath,
 				prettyPath:     file.source.PrettyPath,
-				quotedContents: dataForSourceMaps[result.sourceIndex].quotedContents[0],
+				quotedContents: quotedContents,
 			})
 			continue
 		}
@@ -4288,10 +4292,14 @@ func (c *linkerContext) generateSourceMapForChunk(
 				path.Text = c.fs.Join(c.fs.Dir(file.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: dataForSourceMaps[result.sourceIndex].quotedContents[i],
+				quotedContents: quotedContents,
 			})
 		}
 	}
@@ -4317,14 +4325,16 @@ func (c *linkerContext) generateSourceMapForChunk(
 	j.AddString("]")
 
 	// Write the sourcesContent
-	j.AddString(",\n  \"sourcesContent\": [")
-	for i, item := range items {
-		if i != 0 {
-			j.AddString(", ")
+	if !c.options.ExcludeSourcesContent {
+		j.AddString(",\n  \"sourcesContent\": [")
+		for i, item := range items {
+			if i != 0 {
+				j.AddString(", ")
+			}
+			j.AddBytes(item.quotedContents)
 		}
-		j.AddBytes(item.quotedContents)
+		j.AddString("]")
 	}
-	j.AddString("]")
 
 	// Write the mappings
 	j.AddString(",\n  \"mappings\": \"")

internal/config/config.go

@@ -216,8 +216,10 @@ type Options struct {
 	// If present, metadata about the bundle is written as JSON here
 	AbsMetadataFile string
 
-	SourceMap SourceMap
-	Stdin     *StdinInfo
+	SourceMap             SourceMap
+	ExcludeSourcesContent bool
+
+	Stdin *StdinInfo
 }
 
 type InjectedFile struct {

lib/common.ts

@@ -159,6 +159,7 @@ function flagsForBuildOptions(
   pushCommonFlags(flags, options, keys);
 
   let sourcemap = getFlag(options, keys, 'sourcemap', mustBeStringOrBoolean);
+  let sourcesContent = getFlag(options, keys, 'sourcesContent', mustBeBoolean);
   let bundle = getFlag(options, keys, 'bundle', mustBeBoolean);
   let splitting = getFlag(options, keys, 'splitting', mustBeBoolean);
   let metafile = getFlag(options, keys, 'metafile', mustBeString);
@@ -182,6 +183,7 @@ function flagsForBuildOptions(
   checkForInvalidFlags(options, keys, `in ${callName}() call`);
 
   if (sourcemap) flags.push(`--sourcemap${sourcemap === true ? '' : `=${sourcemap}`}`);
+  if (sourcesContent !== void 0) flags.push(`--sources-content=${sourcesContent}`);
   if (bundle) flags.push('--bundle');
   if (splitting) flags.push('--splitting');
   if (metafile) flags.push(`--metafile=${metafile}`);

lib/types.ts

@@ -7,6 +7,8 @@ export type TreeShaking = true | 'ignore-annotations';
 
 interface CommonOptions {
   sourcemap?: boolean | 'inline' | 'external';
+  sourcesContent?: boolean;
+
   format?: Format;
   globalName?: string;
   target?: string | string[];

pkg/api/api.go

@@ -86,6 +86,13 @@ const (
 	SourceMapExternal
 )
 
+type SourcesContent uint8
+
+const (
+	SourcesContentInclude SourcesContent = iota
+	SourcesContentExclude
+)
+
 type Target uint8
 
 const (
@@ -203,9 +210,11 @@ type BuildOptions struct {
 	ErrorLimit int
 	LogLevel   LogLevel
 
-	Sourcemap SourceMap
-	Target    Target
-	Engines   []Engine
+	Sourcemap      SourceMap
+	SourcesContent SourcesContent
+
+	Target  Target
+	Engines []Engine
 
 	MinifyWhitespace  bool
 	MinifyIdentifiers bool
@@ -281,7 +290,9 @@ type TransformOptions struct {
 	ErrorLimit int
 	LogLevel   LogLevel
 
-	Sourcemap  SourceMap
+	Sourcemap      SourceMap
+	SourcesContent SourcesContent
+
 	Target     Target
 	Format     Format
 	GlobalName string

pkg/api/api_impl.go

@@ -521,34 +521,35 @@ func rebuildImpl(
 			Factory:  validateJSX(log, buildOpts.JSXFactory, "factory"),
 			Fragment: validateJSX(log, buildOpts.JSXFragment, "fragment"),
 		},
-		Defines:              validateDefines(log, buildOpts.Define, buildOpts.Pure),
-		Platform:             validatePlatform(buildOpts.Platform),
-		SourceMap:            validateSourceMap(buildOpts.Sourcemap),
-		MangleSyntax:         buildOpts.MinifySyntax,
-		RemoveWhitespace:     buildOpts.MinifyWhitespace,
-		MinifyIdentifiers:    buildOpts.MinifyIdentifiers,
-		ASCIIOnly:            validateASCIIOnly(buildOpts.Charset),
-		IgnoreDCEAnnotations: validateIgnoreDCEAnnotations(buildOpts.TreeShaking),
-		GlobalName:           validateGlobalName(log, buildOpts.GlobalName),
-		CodeSplitting:        buildOpts.Splitting,
-		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),
-		OutputExtensionJS:    outJS,
-		OutputExtensionCSS:   outCSS,
-		ExtensionToLoader:    validateLoaders(log, buildOpts.Loader),
-		ExtensionOrder:       validateResolveExtensions(log, buildOpts.ResolveExtensions),
-		ExternalModules:      validateExternals(log, realFS, buildOpts.External),
-		TsConfigOverride:     validatePath(log, realFS, buildOpts.Tsconfig),
-		MainFields:           buildOpts.MainFields,
-		PublicPath:           buildOpts.PublicPath,
-		KeepNames:            buildOpts.KeepNames,
-		InjectAbsPaths:       make([]string, len(buildOpts.Inject)),
-		Banner:               buildOpts.Banner,
-		Footer:               buildOpts.Footer,
-		Plugins:              plugins,
+		Defines:               validateDefines(log, buildOpts.Define, buildOpts.Pure),
+		Platform:              validatePlatform(buildOpts.Platform),
+		SourceMap:             validateSourceMap(buildOpts.Sourcemap),
+		ExcludeSourcesContent: buildOpts.SourcesContent == SourcesContentExclude,
+		MangleSyntax:          buildOpts.MinifySyntax,
+		RemoveWhitespace:      buildOpts.MinifyWhitespace,
+		MinifyIdentifiers:     buildOpts.MinifyIdentifiers,
+		ASCIIOnly:             validateASCIIOnly(buildOpts.Charset),
+		IgnoreDCEAnnotations:  validateIgnoreDCEAnnotations(buildOpts.TreeShaking),
+		GlobalName:            validateGlobalName(log, buildOpts.GlobalName),
+		CodeSplitting:         buildOpts.Splitting,
+		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),
+		OutputExtensionJS:     outJS,
+		OutputExtensionCSS:    outCSS,
+		ExtensionToLoader:     validateLoaders(log, buildOpts.Loader),
+		ExtensionOrder:        validateResolveExtensions(log, buildOpts.ResolveExtensions),
+		ExternalModules:       validateExternals(log, realFS, buildOpts.External),
+		TsConfigOverride:      validatePath(log, realFS, buildOpts.Tsconfig),
+		MainFields:            buildOpts.MainFields,
+		PublicPath:            buildOpts.PublicPath,
+		KeepNames:             buildOpts.KeepNames,
+		InjectAbsPaths:        make([]string, len(buildOpts.Inject)),
+		Banner:                buildOpts.Banner,
+		Footer:                buildOpts.Footer,
+		Plugins:               plugins,
 	}
 	for i, path := range buildOpts.Inject {
 		options.InjectAbsPaths[i] = validatePath(log, realFS, path)
@@ -771,6 +772,7 @@ func transformImpl(input string, transformOpts TransformOptions) TransformResult
 		JSX:                     jsx,
 		Defines:                 validateDefines(log, transformOpts.Define, transformOpts.Pure),
 		SourceMap:               validateSourceMap(transformOpts.Sourcemap),
+		ExcludeSourcesContent:   transformOpts.SourcesContent == SourcesContentExclude,
 		OutputFormat:            validateFormat(transformOpts.Format),
 		GlobalName:              validateGlobalName(log, transformOpts.GlobalName),
 		MangleSyntax:            transformOpts.MinifySyntax,

pkg/cli/cli_impl.go

@@ -141,6 +141,23 @@ func parseOptionsImpl(osArgs []string, buildOpts *api.BuildOptions, transformOpt
 			}
 			hasBareSourceMapFlag = false
 
+		case strings.HasPrefix(arg, "--sources-content="):
+			value := arg[len("--sources-content="):]
+			var sourcesContent api.SourcesContent
+			switch value {
+			case "false":
+				sourcesContent = api.SourcesContentExclude
+			case "true":
+				sourcesContent = api.SourcesContentInclude
+			default:
+				return fmt.Errorf("Invalid sources content: %q (valid: false, true)", value)
+			}
+			if buildOpts != nil {
+				buildOpts.SourcesContent = sourcesContent
+			} else {
+				transformOpts.SourcesContent = sourcesContent
+			}
+
 		case strings.HasPrefix(arg, "--sourcefile="):
 			if buildOpts != nil {
 				if buildOpts.Stdin == nil {

scripts/js-api-tests.js

@@ -68,7 +68,8 @@ let buildTests = {
   async sourceMap({ esbuild, testDir }) {
     const input = path.join(testDir, 'in.js')
     const output = path.join(testDir, 'out.js')
-    await writeFileAsync(input, 'exports.foo = 123')
+    const content = 'exports.foo = 123'
+    await writeFileAsync(input, content)
     await esbuild.build({ entryPoints: [input], outfile: output, sourcemap: true })
     const result = require(output)
     assert.strictEqual(result.foo, 123)
@@ -78,12 +79,15 @@ let buildTests = {
     const resultMap = await readFileAsync(output + '.map', 'utf8')
     const json = JSON.parse(resultMap)
     assert.strictEqual(json.version, 3)
+    assert.strictEqual(json.sources[0], path.basename(input))
+    assert.strictEqual(json.sourcesContent[0], content)
   },
 
   async sourceMapExternal({ esbuild, testDir }) {
     const input = path.join(testDir, 'in.js')
     const output = path.join(testDir, 'out.js')
-    await writeFileAsync(input, 'exports.foo = 123')
+    const content = 'exports.foo = 123'
+    await writeFileAsync(input, content)
     await esbuild.build({ entryPoints: [input], outfile: output, sourcemap: 'external' })
     const result = require(output)
     assert.strictEqual(result.foo, 123)
@@ -93,19 +97,60 @@ let buildTests = {
     const resultMap = await readFileAsync(output + '.map', 'utf8')
     const json = JSON.parse(resultMap)
     assert.strictEqual(json.version, 3)
+    assert.strictEqual(json.sources[0], path.basename(input))
+    assert.strictEqual(json.sourcesContent[0], content)
   },
 
   async sourceMapInline({ esbuild, testDir }) {
     const input = path.join(testDir, 'in.js')
     const output = path.join(testDir, 'out.js')
-    await writeFileAsync(input, 'exports.foo = 123')
+    const content = 'exports.foo = 123'
+    await writeFileAsync(input, content)
     await esbuild.build({ entryPoints: [input], outfile: output, sourcemap: 'inline' })
     const result = require(output)
     assert.strictEqual(result.foo, 123)
     const outputFile = await readFileAsync(output, 'utf8')
     const match = /\/\/# sourceMappingURL=data:application\/json;base64,(.*)/.exec(outputFile)
     const json = JSON.parse(Buffer.from(match[1], 'base64').toString())
     assert.strictEqual(json.version, 3)
+    assert.strictEqual(json.sources[0], path.basename(input))
+    assert.strictEqual(json.sourcesContent[0], content)
+  },
+
+  async sourceMapIncludeSourcesContent({ esbuild, testDir }) {
+    const input = path.join(testDir, 'in.js')
+    const output = path.join(testDir, 'out.js')
+    const content = 'exports.foo = 123'
+    await writeFileAsync(input, content)
+    await esbuild.build({ entryPoints: [input], outfile: output, sourcemap: true, sourcesContent: true })
+    const result = require(output)
+    assert.strictEqual(result.foo, 123)
+    const outputFile = await readFileAsync(output, 'utf8')
+    const match = /\/\/# sourceMappingURL=(.*)/.exec(outputFile)
+    assert.strictEqual(match[1], 'out.js.map')
+    const resultMap = await readFileAsync(output + '.map', 'utf8')
+    const json = JSON.parse(resultMap)
+    assert.strictEqual(json.version, 3)
+    assert.strictEqual(json.sources[0], path.basename(input))
+    assert.strictEqual(json.sourcesContent[0], content)
+  },
+
+  async sourceMapExcludeSourcesContent({ esbuild, testDir }) {
+    const input = path.join(testDir, 'in.js')
+    const output = path.join(testDir, 'out.js')
+    const content = 'exports.foo = 123'
+    await writeFileAsync(input, content)
+    await esbuild.build({ entryPoints: [input], outfile: output, sourcemap: true, sourcesContent: false })
+    const result = require(output)
+    assert.strictEqual(result.foo, 123)
+    const outputFile = await readFileAsync(output, 'utf8')
+    const match = /\/\/# sourceMappingURL=(.*)/.exec(outputFile)
+    assert.strictEqual(match[1], 'out.js.map')
+    const resultMap = await readFileAsync(output + '.map', 'utf8')
+    const json = JSON.parse(resultMap)
+    assert.strictEqual(json.version, 3)
+    assert.strictEqual(json.sources[0], path.basename(input))
+    assert.strictEqual(json.sourcesContent, void 0)
   },
 
   async resolveExtensionOrder({ esbuild, testDir }) {