start work on code generation

README.md

@@ -213,13 +213,14 @@ Options:
   --target=...          Language target (default esnext)
   --platform=...        Platform target (browser or node, default browser)
   --external:M          Exclude module M from the bundle
-  --format=...          Output format (iife, cjs, es)
+  --format=...          Output format (iife, cjs, esm)
   --color=...           Force use of color terminal escapes (true or false)
 
   --minify              Sets all --minify-* flags
   --minify-whitespace   Remove whitespace
   --minify-identifiers  Shorten identifiers
   --minify-syntax       Use equivalent but shorter syntax
+  --tree-shaking        Remove unused code from the bundle
 
   --define:K=V          Substitute K with V while parsing
   --jsx-factory=...     What to use instead of React.createElement

cmd/esbuild/main.go

@@ -33,13 +33,14 @@ Options:
   --target=...          Language target (default esnext)
   --platform=...        Platform target (browser or node, default browser)
   --external:M          Exclude module M from the bundle
-  --format=...          Output format (iife, cjs, es)
+  --format=...          Output format (iife, cjs, esm)
   --color=...           Force use of color terminal escapes (true or false)
 
   --minify              Sets all --minify-* flags
   --minify-whitespace   Remove whitespace
   --minify-identifiers  Shorten identifiers
   --minify-syntax       Use equivalent but shorter syntax
+  --tree-shaking        Remove unused code from the bundle
 
   --define:K=V          Substitute K with V while parsing
   --jsx-factory=...     What to use instead of React.createElement
@@ -219,6 +220,9 @@ func parseArgs(fs fs.FS, rawArgs []string) (argsObject, error) {
 		case arg == "--minify-identifiers":
 			args.bundleOptions.MinifyIdentifiers = true
 
+		case arg == "--tree-shaking":
+			args.bundleOptions.TreeShaking = true
+
 		case arg == "--sourcemap":
 			args.bundleOptions.SourceMap = bundler.SourceMapLinkedWithComment
 
@@ -336,10 +340,10 @@ func parseArgs(fs fs.FS, rawArgs []string) (argsObject, error) {
 				args.bundleOptions.OutputFormat = bundler.FormatIIFE
 			case "cjs":
 				args.bundleOptions.OutputFormat = bundler.FormatCommonJS
-			case "es":
+			case "esm":
 				args.bundleOptions.OutputFormat = bundler.FormatESModule
 			default:
-				return argsObject{}, fmt.Errorf("Valid formats: iife, cjs, es")
+				return argsObject{}, fmt.Errorf("Valid formats: iife, cjs, esm")
 			}
 
 		case strings.HasPrefix(arg, "--color="):

internal/ast/ast.go

@@ -995,6 +995,10 @@ func (sm SymbolMap) IncrementUseCountEstimate(ref Ref) {
 	sm.Outer[ref.OuterIndex][ref.InnerIndex].UseCountEstimate++
 }
 
+func (sm SymbolMap) SetName(ref Ref, name string) {
+	sm.Outer[ref.OuterIndex][ref.InnerIndex].Name = name
+}
+
 func (sm SymbolMap) SetNamespaceAlias(ref Ref, alias NamespaceAlias) {
 	sm.Outer[ref.OuterIndex][ref.InnerIndex].NamespaceAlias = &alias
 }
@@ -1037,6 +1041,7 @@ type AST struct {
 	ModuleScope *Scope
 	ExportsRef  Ref
 	ModuleRef   Ref
+	WrapperRef  Ref
 
 	// These are used when bundling.
 	NamedImports map[Ref]NamedImport

internal/bundler/bundler.go

@@ -364,6 +364,9 @@ type BundleOptions struct {
 	// false: imports are left alone and the file is passed through as-is
 	IsBundling bool
 
+	// If true, unused code is removed. If false, all code is kept.
+	TreeShaking bool
+
 	AbsOutputFile     string
 	AbsOutputDir      string
 	RemoveWhitespace  bool
@@ -1304,13 +1307,12 @@ func (b *Bundle) renameOrMinifyAllSymbolsInRuntime(files []file, symbols ast.Sym
 	reservedNames := computeReservedNames(moduleScopes, symbols)
 
 	// We're only renaming symbols in the runtime
-	runtimeModuleScope := []*ast.Scope{files[runtimeSourceIndex].ast.ModuleScope}
+	scope := files[runtimeSourceIndex].ast.ModuleScope
 
 	if options.MinifyIdentifiers {
-		nextName := 54 * 54 // Use names ending with '$' to avoid taking good short names
-		minifyAllSymbols(reservedNames, runtimeModuleScope, symbols, nextName)
+		minifyAllSymbols(reservedNames, []*ast.Scope{scope}, scope.Children, symbols)
 	} else {
-		renameAllSymbols(reservedNames, runtimeModuleScope, symbols)
+		renameAllSymbols(reservedNames, []*ast.Scope{scope}, scope.Children, symbols)
 	}
 }
 
@@ -1345,10 +1347,15 @@ func (b *Bundle) renameOrMinifyAllSymbols(files []file, symbols ast.SymbolMap, g
 		}
 	}
 
+	nestedScopes := []*ast.Scope{}
+	for _, scope := range moduleScopes {
+		nestedScopes = append(nestedScopes, scope.Children...)
+	}
+
 	if options.MinifyIdentifiers {
-		minifyAllSymbols(reservedNames, moduleScopes, symbols, 0 /* nextName */)
+		minifyAllSymbols(reservedNames, moduleScopes, nestedScopes, symbols)
 	} else {
-		renameAllSymbols(reservedNames, moduleScopes, symbols)
+		renameAllSymbols(reservedNames, moduleScopes, nestedScopes, symbols)
 	}
 }
 
@@ -1565,9 +1572,8 @@ func (b *Bundle) compileIndependent(log logging.Log, options *BundleOptions) []B
 }
 
 func (b *Bundle) compileBundle(log logging.Log, options *BundleOptions) []BundleResult {
-	c := newLinkerContext(log, b.sources, b.files, b.entryPoints)
-	c.link()
-	return b.oldCompileBundle(log, options)
+	c := newLinkerContext(options, log, b.fs, b.sources, b.files, b.entryPoints)
+	return c.link()
 }
 
 func (b *Bundle) oldCompileBundle(log logging.Log, options *BundleOptions) []BundleResult {