add file loader (#135)

README.md

@@ -238,7 +238,7 @@ Options:
   --jsx-factory=...     What to use instead of React.createElement
   --jsx-fragment=...    What to use instead of React.Fragment
   --loader:X=L          Use loader L to load file extension X, where L is
-                        one of: js, jsx, ts, tsx, json, text, base64, dataurl
+                        one of: js, jsx, ts, tsx, json, text, base64, file, dataurl
 
 Advanced options:
   --version                 Print the current version and exit

cmd/esbuild/main.go

@@ -46,7 +46,7 @@ Options:
   --jsx-factory=...     What to use instead of React.createElement
   --jsx-fragment=...    What to use instead of React.Fragment
   --loader:X=L          Use loader L to load file extension X, where L is
-                        one of: js, jsx, ts, tsx, json, text, base64, dataurl
+                        one of: js, jsx, ts, tsx, json, text, base64, file, dataurl
 
 Advanced options:
   --version                 Print the current version and exit (` + esbuildVersion + `)
@@ -176,6 +176,8 @@ func (args *argsObject) parseLoader(text string) bundler.Loader {
 		return bundler.LoaderBase64
 	case "dataurl":
 		return bundler.LoaderDataURL
+	case "file":
+		return bundler.LoaderFile
 	default:
 		return bundler.LoaderNone
 	}
@@ -645,6 +647,17 @@ func run(fs fs.FS, args argsObject) {
 		}
 		args.logInfo(fmt.Sprintf("Wrote to %s (%s)", path, toSize(len(item.JsContents))))
 
+		// Write out the additional files
+		for _, file := range item.AdditionalFiles {
+			if file.Path != "" {
+				err := ioutil.WriteFile(file.Path, []byte(file.Contents), 0644)
+				path := resolver.PrettyPath(file.Path)
+				if err != nil {
+					exitWithError(fmt.Sprintf("Failed to write to %s (%s)", path, err.Error()))
+				}
+				args.logInfo(fmt.Sprintf("Wrote to %s (%s)", path, toSize(len(file.Contents))))
+			}
+		}
 		// Also write the source map
 		if item.SourceMapAbsPath != "" {
 			err := ioutil.WriteFile(item.SourceMapAbsPath, item.SourceMapContents, 0644)

go.mod

@@ -2,4 +2,7 @@ module github.com/evanw/esbuild
 
 go 1.13
 
-require golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3
+require (
+	github.com/kylelemons/godebug v1.1.0
+	golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3
+)

go.sum

@@ -1,2 +1,4 @@
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3 h1:5B6i6EAiSYyejWfvc5Rc9BbI3rzIsrrXfAQBWnYfn+w=
 golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

internal/bundler/bundler.go

@@ -7,7 +7,7 @@ import (
 	"mime"
 	"net/http"
 	"os"
-	"strings"
+	"path"
 	"sync"
 
 	"github.com/evanw/esbuild/internal/ast"
@@ -33,6 +33,9 @@ type file struct {
 	// This is used by the printer to write out the source index for modules that
 	// are referenced in the AST.
 	resolvedImports map[string]uint32
+
+	// This is used for file-loader to emit files
+	additionalFile AdditionalFile
 }
 
 func (f *file) resolveImport(path ast.Path) (uint32, bool) {
@@ -51,15 +54,16 @@ type Bundle struct {
 }
 
 type parseResult struct {
-	source logging.Source
-	ast    ast.AST
-	ok     bool
+	source     logging.Source
+	ast        ast.AST
+	ok         bool
+	outputPath string
 }
 
 func parseFile(
 	log logging.Log,
 	res resolver.Resolver,
-	path string,
+	sourcePath string,
 	sourceIndex uint32,
 	isStdin bool,
 	importSource logging.Source,
@@ -69,9 +73,9 @@ func parseFile(
 	bundleOptions BundleOptions,
 	results chan parseResult,
 ) {
-	prettyPath := path
+	prettyPath := sourcePath
 	if !isStdin {
-		prettyPath = res.PrettyPath(path)
+		prettyPath = res.PrettyPath(sourcePath)
 	}
 	contents := ""
 
@@ -87,9 +91,9 @@ func parseFile(
 			contents = string(bytes)
 		} else {
 			var ok bool
-			contents, ok = res.Read(path)
+			contents, ok = res.Read(sourcePath)
 			if !ok {
-				log.AddRangeError(importSource, pathRange, fmt.Sprintf("Could not read from file: %s", path))
+				log.AddRangeError(importSource, pathRange, fmt.Sprintf("Could not read from file: %s", sourcePath))
 				results <- parseResult{}
 				return
 			}
@@ -99,16 +103,13 @@ func parseFile(
 	source := logging.Source{
 		Index:        sourceIndex,
 		IsStdin:      isStdin,
-		AbsolutePath: path,
+		AbsolutePath: sourcePath,
 		PrettyPath:   prettyPath,
 		Contents:     contents,
 	}
 
 	// Get the file extension
-	extension := ""
-	if lastDot := strings.LastIndexByte(path, '.'); lastDot >= 0 {
-		extension = path[lastDot:]
-	}
+	extension := path.Ext(sourcePath)
 
 	// Pick the loader based on the file extension
 	loader := bundleOptions.ExtensionToLoader[extension]
@@ -121,39 +122,39 @@ func parseFile(
 	switch loader {
 	case LoaderJS:
 		ast, ok := parser.Parse(log, source, parseOptions)
-		results <- parseResult{source, ast, ok}
+		results <- parseResult{source, ast, ok, ""}
 
 	case LoaderJSX:
 		parseOptions.JSX.Parse = true
 		ast, ok := parser.Parse(log, source, parseOptions)
-		results <- parseResult{source, ast, ok}
+		results <- parseResult{source, ast, ok, ""}
 
 	case LoaderTS:
 		parseOptions.TS.Parse = true
 		ast, ok := parser.Parse(log, source, parseOptions)
-		results <- parseResult{source, ast, ok}
+		results <- parseResult{source, ast, ok, ""}
 
 	case LoaderTSX:
 		parseOptions.TS.Parse = true
 		parseOptions.JSX.Parse = true
 		ast, ok := parser.Parse(log, source, parseOptions)
-		results <- parseResult{source, ast, ok}
+		results <- parseResult{source, ast, ok, ""}
 
 	case LoaderJSON:
 		expr, ok := parser.ParseJSON(log, source, parser.ParseJSONOptions{})
 		ast := parser.ModuleExportsAST(log, source, parseOptions, expr)
-		results <- parseResult{source, ast, ok}
+		results <- parseResult{source, ast, ok, ""}
 
 	case LoaderText:
 		expr := ast.Expr{ast.Loc{0}, &ast.EString{lexer.StringToUTF16(source.Contents)}}
 		ast := parser.ModuleExportsAST(log, source, parseOptions, expr)
-		results <- parseResult{source, ast, true}
+		results <- parseResult{source, ast, true, ""}
 
 	case LoaderBase64:
 		encoded := base64.StdEncoding.EncodeToString([]byte(source.Contents))
 		expr := ast.Expr{ast.Loc{0}, &ast.EString{lexer.StringToUTF16(encoded)}}
 		ast := parser.ModuleExportsAST(log, source, parseOptions, expr)
-		results <- parseResult{source, ast, true}
+		results <- parseResult{source, ast, true, ""}
 
 	case LoaderDataURL:
 		mimeType := mime.TypeByExtension(extension)
@@ -164,10 +165,20 @@ func parseFile(
 		url := "data:" + mimeType + ";base64," + encoded
 		expr := ast.Expr{ast.Loc{0}, &ast.EString{lexer.StringToUTF16(url)}}
 		ast := parser.ModuleExportsAST(log, source, parseOptions, expr)
-		results <- parseResult{source, ast, true}
+		results <- parseResult{source, ast, true, ""}
+
+	case LoaderFile:
+		url := path.Base(sourcePath)
+		targetFolder := bundleOptions.AbsOutputDir
+		if targetFolder == "" {
+			targetFolder = path.Dir(bundleOptions.AbsOutputFile)
+		}
+		expr := ast.Expr{ast.Loc{0}, &ast.EString{lexer.StringToUTF16(url)}}
+		ast := parser.ModuleExportsAST(log, source, parseOptions, expr)
+		results <- parseResult{source, ast, true, path.Join(targetFolder, url)}
 
 	default:
-		log.AddRangeError(importSource, pathRange, fmt.Sprintf("File extension not supported: %s", path))
+		log.AddRangeError(importSource, pathRange, fmt.Sprintf("File extension not supported: %s", sourcePath))
 		results <- parseResult{}
 	}
 }
@@ -205,7 +216,7 @@ func ScanBundle(
 			runtimeParseOptions.IsBundling = true
 
 			ast, ok := parser.Parse(log, source, runtimeParseOptions)
-			results <- parseResult{source, ast, ok}
+			results <- parseResult{source, ast, ok, ""}
 		}()
 	}
 
@@ -286,7 +297,8 @@ func ScanBundle(
 		}
 
 		sources[source.Index] = source
-		files[source.Index] = file{result.ast, resolvedImports}
+
+		files[source.Index] = file{result.ast, resolvedImports, AdditionalFile{result.outputPath, source.Contents}}
 	}
 
 	return Bundle{fs, sources, files, entryPoints}
@@ -304,6 +316,7 @@ const (
 	LoaderText
 	LoaderBase64
 	LoaderDataURL
+	LoaderFile
 )
 
 func DefaultExtensionToLoaderMap() map[string]Loader {
@@ -355,11 +368,17 @@ type BundleOptions struct {
 	omitRuntimeForTests bool
 }
 
+type AdditionalFile struct {
+	Path     string
+	Contents string
+}
+
 type BundleResult struct {
 	JsAbsPath         string
 	JsContents        []byte
 	SourceMapAbsPath  string
 	SourceMapContents []byte
+	AdditionalFiles   []AdditionalFile
 }
 
 type lineColumnOffset struct {
@@ -415,6 +434,13 @@ func (b *Bundle) Compile(log logging.Log, options BundleOptions) []BundleResult
 	var results []BundleResult
 	for _, group := range resultGroups {
 		results = append(results, group...)
+		for _, bundle := range group {
+			for _, additionalFile := range bundle.AdditionalFiles {
+				if additionalFile.Path != "" {
+					results = append(results, BundleResult{additionalFile.Path, []byte(additionalFile.Contents), "", []byte(""), []AdditionalFile{}})
+				}
+			}
+		}
 	}
 	return results
 }

internal/bundler/bundler_test.go

@@ -1,19 +1,28 @@
 package bundler
 
 import (
+	"fmt"
 	"path"
+	"strings"
 	"testing"
 
 	"github.com/evanw/esbuild/internal/fs"
 	"github.com/evanw/esbuild/internal/logging"
 	"github.com/evanw/esbuild/internal/parser"
 	"github.com/evanw/esbuild/internal/printer"
 	"github.com/evanw/esbuild/internal/resolver"
+	"github.com/kylelemons/godebug/diff"
 )
 
 func assertEqual(t *testing.T, a interface{}, b interface{}) {
 	if a != b {
-		t.Fatalf("%s != %s", a, b)
+		stringA := fmt.Sprintf("%v", a)
+		stringB := fmt.Sprintf("%v", b)
+		if strings.Contains(stringA, "\n") {
+			t.Fatal(diff.Diff(stringA, stringB))
+		} else {
+			t.Fatalf("%s != %s", a, b)
+		}
 	}
 }
 
@@ -2739,6 +2748,40 @@ func testAutoDetectMimeTypeFromExtension(t *testing.T) {
 	})
 }
 
+func TestLoaderFile(t *testing.T) {
+	expectBundled(t, bundled{
+		files: map[string]string{
+			"/entry.js": `
+				console.log(require('./test.svg'))
+			`,
+			"/test.svg": "<svg></svg>",
+		},
+		entryPaths: []string{"/entry.js"},
+		parseOptions: parser.ParseOptions{
+			IsBundling: true,
+		},
+		bundleOptions: BundleOptions{
+			IsBundling:   true,
+			AbsOutputDir: "/out/",
+			ExtensionToLoader: map[string]Loader{
+				".js":  LoaderJS,
+				".svg": LoaderFile,
+			},
+		},
+		expected: map[string]string{
+			"/out/test.svg": "<svg></svg>",
+			"/out/entry.js": `// /test.svg
+var require_test = __commonJS((exports, module) => {
+  module.exports = "test.svg";
+});
+
+// /entry.js
+console.log(require_test());
+`,
+		},
+	})
+}
+
 func TestRequireBadExtension(t *testing.T) {
 	expectBundled(t, bundled{
 		files: map[string]string{

internal/bundler/linker.go

@@ -1714,6 +1714,7 @@ func (c *linkerContext) generateCodeForFileInChunk(
 }
 
 func (c *linkerContext) generateChunk(chunk chunkMeta) BundleResult {
+	additionalFiles := []AdditionalFile{}
 	filesInChunkInOrder := c.chunkFileOrder(chunk)
 	compileResults := make([]compileResult, 0, len(filesInChunkInOrder))
 	runtimeMembers := c.files[ast.RuntimeSourceIndex].ast.ModuleScope.Members
@@ -1738,6 +1739,9 @@ func (c *linkerContext) generateChunk(chunk chunkMeta) BundleResult {
 	// Generate JavaScript for each file in parallel
 	waitGroup := sync.WaitGroup{}
 	for _, sourceIndex := range filesInChunkInOrder {
+		file := c.files[sourceIndex]
+
+		additionalFiles = append(additionalFiles, file.additionalFile)
 		// Skip the runtime in test output
 		if sourceIndex == ast.RuntimeSourceIndex && c.options.omitRuntimeForTests {
 			continue
@@ -1797,7 +1801,6 @@ func (c *linkerContext) generateChunk(chunk chunkMeta) BundleResult {
 	var entryPointTail *printer.PrintResult
 	for _, compileResult := range compileResults {
 		isRuntime := compileResult.sourceIndex == ast.RuntimeSourceIndex
-
 		// If this is the entry point, it may have some extra code to stick at the
 		// end of the chunk after all modules have evaluated
 		if compileResult.entryPointTail != nil {
@@ -1856,7 +1859,8 @@ func (c *linkerContext) generateChunk(chunk chunkMeta) BundleResult {
 	}
 
 	result := BundleResult{
-		JsAbsPath: c.fs.Join(c.options.AbsOutputDir, chunk.name),
+		AdditionalFiles: additionalFiles,
+		JsAbsPath:       c.fs.Join(c.options.AbsOutputDir, chunk.name),
 	}
 
 	if c.options.SourceMap != SourceMapNone {

npm/esbuild/lib/main.d.ts

@@ -1,7 +1,7 @@
 export declare type Target = 'esnext' | 'es6' | 'es2015' | 'es2016' | 'es2017' | 'es2018' | 'es2019' | 'es2020';
 export declare type Platform = 'browser' | 'node';
 export declare type Format = 'iife' | 'cjs' | 'esm';
-export declare type Loader = 'js' | 'jsx' | 'ts' | 'tsx' | 'json' | 'text' | 'base64' | 'dataurl';
+export declare type Loader = 'js' | 'jsx' | 'ts' | 'tsx' | 'json' | 'text' | 'base64' | 'file' | 'dataurl';
 export declare type LogLevel = 'info' | 'warning' | 'error';
 
 interface CommonOptions {