Actually transform KindCommonJSExport in declaration emit (#1962)

Author: weswigham

internal/transformers/declarations/transform.go

@@ -120,7 +120,8 @@ func (tx *DeclarationTransformer) visit(node *ast.Node) *ast.Node {
 		ast.KindJSImportDeclaration,
 		ast.KindExportDeclaration,
 		ast.KindJSExportAssignment,
-		ast.KindExportAssignment:
+		ast.KindExportAssignment,
+		ast.KindCommonJSExport:
 		return tx.visitDeclarationStatements(node)
 	// statements we elide
 	case ast.KindBreakStatement,
@@ -924,6 +925,80 @@ func (tx *DeclarationTransformer) visitDeclarationStatements(input *ast.Node) *a
 			tx.rewriteModuleSpecifier(input, input.AsExportDeclaration().ModuleSpecifier),
 			tx.tryGetResolutionModeOverride(input.AsExportDeclaration().Attributes),
 		)
+	case ast.KindCommonJSExport:
+		if ast.IsSourceFile(input.Parent) {
+			tx.resultHasExternalModuleIndicator = true
+		}
+		tx.resultHasScopeMarker = true
+		name := input.AsCommonJSExport().Name()
+		if ast.IsIdentifier(name) {
+			if name.AsIdentifier().Text == "default" {
+				// const _default: Type; export default _default;
+				newId := tx.Factory().NewUniqueNameEx("_default", printer.AutoGenerateOptions{Flags: printer.GeneratedIdentifierFlagsOptimistic})
+				tx.state.getSymbolAccessibilityDiagnostic = func(_ printer.SymbolAccessibilityResult) *SymbolAccessibilityDiagnostic {
+					return &SymbolAccessibilityDiagnostic{
+						diagnosticMessage: diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
+						errorNode:         input,
+					}
+				}
+				tx.tracker.PushErrorFallbackNode(input)
+				type_ := tx.ensureType(input, false)
+				varDecl := tx.Factory().NewVariableDeclaration(newId, nil, type_, nil)
+				tx.tracker.PopErrorFallbackNode()
+				var modList *ast.ModifierList
+				if tx.needsDeclare {
+					modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindDeclareKeyword)})
+				} else {
+					modList = tx.Factory().NewModifierList([]*ast.Node{})
+				}
+				statement := tx.Factory().NewVariableStatement(modList, tx.Factory().NewVariableDeclarationList(ast.NodeFlagsConst, tx.Factory().NewNodeList([]*ast.Node{varDecl})))
+
+				assignment := tx.Factory().NewExportAssignment(input.Modifiers(), false, nil, newId)
+				// Remove comments from the export declaration and copy them onto the synthetic _default declaration
+				tx.preserveJsDoc(statement, input)
+				tx.removeAllComments(assignment)
+				return tx.Factory().NewSyntaxList([]*ast.Node{statement, assignment})
+			} else {
+				// export var name: Type
+				tx.tracker.PushErrorFallbackNode(input)
+				type_ := tx.ensureType(input, false)
+				varDecl := tx.Factory().NewVariableDeclaration(name, nil, type_, nil)
+				tx.tracker.PopErrorFallbackNode()
+				var modList *ast.ModifierList
+				if tx.needsDeclare {
+					modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindExportKeyword), tx.Factory().NewModifier(ast.KindDeclareKeyword)})
+				} else {
+					modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindExportKeyword)})
+				}
+				return tx.Factory().NewVariableStatement(modList, tx.Factory().NewVariableDeclarationList(ast.NodeFlagsNone, tx.Factory().NewNodeList([]*ast.Node{varDecl})))
+			}
+		} else {
+			// const _exported: Type; export {_exported as "name"};
+			newId := tx.Factory().NewUniqueNameEx("_exported", printer.AutoGenerateOptions{Flags: printer.GeneratedIdentifierFlagsOptimistic})
+			tx.state.getSymbolAccessibilityDiagnostic = func(_ printer.SymbolAccessibilityResult) *SymbolAccessibilityDiagnostic {
+				return &SymbolAccessibilityDiagnostic{
+					diagnosticMessage: diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
+					errorNode:         input,
+				}
+			}
+			tx.tracker.PushErrorFallbackNode(input)
+			type_ := tx.ensureType(input, false)
+			varDecl := tx.Factory().NewVariableDeclaration(newId, nil, type_, nil)
+			tx.tracker.PopErrorFallbackNode()
+			var modList *ast.ModifierList
+			if tx.needsDeclare {
+				modList = tx.Factory().NewModifierList([]*ast.Node{tx.Factory().NewModifier(ast.KindDeclareKeyword)})
+			} else {
+				modList = tx.Factory().NewModifierList([]*ast.Node{})
+			}
+			statement := tx.Factory().NewVariableStatement(modList, tx.Factory().NewVariableDeclarationList(ast.NodeFlagsConst, tx.Factory().NewNodeList([]*ast.Node{varDecl})))
+
+			assignment := tx.Factory().NewExportDeclaration(nil, false, tx.Factory().NewNamedExports(tx.Factory().NewNodeList([]*ast.Node{tx.Factory().NewExportSpecifier(false, newId, name)})), nil, nil)
+			// Remove comments from the export declaration and copy them onto the synthetic _default declaration
+			tx.preserveJsDoc(statement, input)
+			tx.removeAllComments(assignment)
+			return tx.Factory().NewSyntaxList([]*ast.Node{statement, assignment})
+		}
 	case ast.KindExportAssignment, ast.KindJSExportAssignment:
 		if ast.IsSourceFile(input.Parent) {
 			tx.resultHasExternalModuleIndicator = true

internal/transformers/declarations/util.go

@@ -64,7 +64,8 @@ func hasInferredType(node *ast.Node) bool {
 		ast.KindPropertyAssignment,
 		ast.KindShorthandPropertyAssignment,
 		ast.KindJSDocParameterTag,
-		ast.KindJSDocPropertyTag:
+		ast.KindJSDocPropertyTag,
+		ast.KindCommonJSExport:
 		return true
 	default:
 		// assertType<never>(node); // !!!

testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.js

@@ -0,0 +1,22 @@
+//// [tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts] ////
+
+//// [index.js]
+exports.default = () => {
+    return 1234;
+}
+
+
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+export var default = () => {
+    return 1234;
+};
+exports.default = () => {
+    return 1234;
+};
+
+
+//// [index.d.ts]
+declare const _default: () => number;
+export default _default;

testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.symbols

@@ -0,0 +1,11 @@
+//// [tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts] ////
+
+=== index.js ===
+exports.default = () => {
+>exports.default : Symbol(default, Decl(index.js, 0, 0))
+>exports : Symbol("index", Decl(index.js, 0, 0))
+>default : Symbol(default, Decl(index.js, 0, 0))
+
+    return 1234;
+}
+

testdata/baselines/reference/compiler/jsDeclarationExportDefaultAssignmentCrash.types

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/jsDeclarationExportDefaultAssignmentCrash.ts] ////
+
+=== index.js ===
+exports.default = () => {
+>exports.default = () => {    return 1234;} : () => number
+>exports.default : () => number
+>exports : typeof import("index")
+>default : () => number
+>() => {    return 1234;} : () => number
+
+    return 1234;
+>1234 : 1234
+}
+

testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js

@@ -17,4 +17,4 @@ declare const _default: {
     customSymbol: symbol;
 };
 export = _default;
-export var customSymbol2 = Symbol("custom");
+export declare var customSymbol2: symbol;

testdata/baselines/reference/submodule/compiler/jsExportAssignmentNonMutableLocation.js.diff

@@ -10,4 +10,4 @@
 +    customSymbol: symbol;
 +};
 +export = _default;
-+export var customSymbol2 = Symbol("custom");
++export declare var customSymbol2: symbol;

testdata/baselines/reference/submodule/compiler/modulePreserve4.js

@@ -198,7 +198,7 @@ export {}; // Silly test harness
 
 //// [a.d.ts]
 export declare const x = 0;
-export var y = 0;
+export declare var y: number;
 //// [b.d.ts]
 declare const _default: number;
 export default _default;
@@ -217,16 +217,15 @@ export = _default;
 declare const _default: number;
 export default _default;
 //// [g.d.ts]
-export var default = 0;
-export {};
+declare const _default: number;
+export default _default;
 //// [main1.d.ts]
 export {};
 //// [main2.d.mts]
 export {};
 //// [main3.d.cts]
 export {};
 //// [main4.d.cts]
-export var x = require("./g");
-export {};
+export declare var x: typeof import("./g");
 //// [dummy.d.ts]
 export {};

testdata/baselines/reference/submodule/compiler/modulePreserve4.js.diff

@@ -30,7 +30,7 @@
  //// [a.d.ts]
 -export const x: 0;
 +export declare const x = 0;
-+export var y = 0;
++export declare var y: number;
  //// [b.d.ts]
 -declare const _default: 0;
 +declare const _default: number;
@@ -50,18 +50,15 @@
  export default _default;
  //// [g.d.ts]
 -declare const _default: 0;
--export default _default;
-+export var default = 0;
-+export {};
++declare const _default: number;
+ export default _default;
  //// [main1.d.ts]
  export {};
- //// [main2.d.mts]
 @@= skipped -15, +15 lines =@@
  //// [main3.d.cts]
  export {};
  //// [main4.d.cts]
 -export const x: typeof import("./g");
-+export var x = require("./g");
-+export {};
++export declare var x: typeof import("./g");
  //// [dummy.d.ts]
  export {};

testdata/baselines/reference/submodule/conformance/assignmentToVoidZero1.js

@@ -21,7 +21,6 @@ exports.y = 2;
 
 
 //// [assignmentToVoidZero1.d.ts]
-export var y = exports.x = void 0;
-export var x = 1;
-export var y = 2;
-export {};
+export declare var y: undefined;
+export declare var x: number;
+export declare var y: undefined;