vendor tsgo

tools/tsgo/internal/transformers/estransforms/usestrict.go

@@ -0,0 +1,50 @@
+package estransforms
+
+import (
+	"github.com/microsoft/typescript-go/internal/ast"
+	"github.com/microsoft/typescript-go/internal/core"
+	"github.com/microsoft/typescript-go/internal/transformers"
+)
+
+func NewUseStrictTransformer(opts *transformers.TransformOptions) *transformers.Transformer {
+	tx := &useStrictTransformer{
+		compilerOptions:           opts.CompilerOptions,
+		getEmitModuleFormatOfFile: opts.GetEmitModuleFormatOfFile,
+	}
+	return tx.NewTransformer(tx.visit, opts.Context)
+}
+
+type useStrictTransformer struct {
+	transformers.Transformer
+	compilerOptions           *core.CompilerOptions
+	getEmitModuleFormatOfFile func(file ast.HasFileName) core.ModuleKind
+}
+
+func (tx *useStrictTransformer) visit(node *ast.Node) *ast.Node {
+	if node.Kind != ast.KindSourceFile {
+		return node
+	}
+	return tx.visitSourceFile(node.AsSourceFile())
+}
+
+func (tx *useStrictTransformer) visitSourceFile(node *ast.SourceFile) *ast.Node {
+	if node.ScriptKind == core.ScriptKindJSON {
+		return node.AsNode()
+	}
+
+	isExternalModule := ast.IsExternalModule(node)
+	moduleKind := tx.compilerOptions.GetEmitModuleKind()
+	format := tx.getEmitModuleFormatOfFile(node)
+
+	// ESM is always strict. If the file is ESM, and CJS emit
+	// has not been requested, then skip adding "use strict".
+	if isExternalModule && moduleKind >= core.ModuleKindES2015 &&
+		(moduleKind == core.ModuleKindPreserve || format >= core.ModuleKindES2015) {
+		return node.AsNode()
+	}
+
+	statements := tx.Factory().EnsureUseStrict(node.Statements.Nodes)
+	statementList := tx.Factory().NewNodeList(statements)
+	statementList.Loc = node.Statements.Loc
+	return tx.Factory().UpdateSourceFile(node, statementList, node.EndOfFileToken).AsSourceFile().AsNode()
+}