Allow allowJs and declaration to be used together

This intorduces a new symbol-based declaration emitter - currently this
is only used for JSON and JavaScript, as the output is likely worse than
what the other declaration emitter is capable of. In addition, it is
still incomplete - it does not yet support serializaing namespaces.

Author: weswigham

src/compiler/checker.ts

@@ -97,9 +97,7 @@ namespace ts {
                 comparePaths(sourceFile.fileName, ownOutputFilePath, host.getCurrentDirectory(), !host.useCaseSensitiveFileNames()) === Comparison.EqualTo;
             const jsFilePath = options.emitDeclarationOnly || isJsonEmittedToSameLocation ? undefined : ownOutputFilePath;
             const sourceMapFilePath = !jsFilePath || isJsonSourceFile(sourceFile) ? undefined : getSourceMapFilePath(jsFilePath, options);
-            // For legacy reasons (ie, we have baselines capturing the behavior), js files don't report a .d.ts output path - this would only matter if `declaration` and `allowJs` were both on, which is currently an error
-            const isJs = isSourceFileJS(sourceFile);
-            const declarationFilePath = ((forceDtsPaths || getEmitDeclarations(options)) && !isJs) ? getDeclarationEmitOutputFilePath(sourceFile.fileName, host) : undefined;
+            const declarationFilePath = (forceDtsPaths || getEmitDeclarations(options)) ? getDeclarationEmitOutputFilePath(sourceFile.fileName, host) : undefined;
             const declarationMapPath = declarationFilePath && getAreDeclarationMapsEnabled(options) ? declarationFilePath + ".map" : undefined;
             return { jsFilePath, sourceMapFilePath, declarationFilePath, declarationMapPath, buildInfoPath: undefined };
         }
@@ -351,17 +349,16 @@ namespace ts {
             declarationFilePath: string | undefined,
             declarationMapPath: string | undefined,
             relativeToBuildInfo: (path: string) => string) {
-            if (!sourceFileOrBundle || !(declarationFilePath && !isInJSFile(sourceFileOrBundle))) {
+            if (!sourceFileOrBundle || !declarationFilePath) {
                 return;
             }
             const sourceFiles = isSourceFile(sourceFileOrBundle) ? [sourceFileOrBundle] : sourceFileOrBundle.sourceFiles;
             // Setup and perform the transformation to retrieve declarations from the input files
-            const nonJsFiles = filter(sourceFiles, isSourceFileNotJS);
-            const inputListOrBundle = (compilerOptions.outFile || compilerOptions.out) ? [createBundle(nonJsFiles, !isSourceFile(sourceFileOrBundle) ? sourceFileOrBundle.prepends : undefined)] : nonJsFiles;
+            const inputListOrBundle = (compilerOptions.outFile || compilerOptions.out) ? [createBundle(sourceFiles, !isSourceFile(sourceFileOrBundle) ? sourceFileOrBundle.prepends : undefined)] : sourceFiles;
             if (emitOnlyDtsFiles && !getEmitDeclarations(compilerOptions)) {
                 // Checker wont collect the linked aliases since thats only done when declaration is enabled.
                 // Do that here when emitting only dts files
-                nonJsFiles.forEach(collectLinkedAliases);
+                sourceFiles.forEach(collectLinkedAliases);
             }
             const declarationTransform = transformNodes(resolver, host, compilerOptions, inputListOrBundle, declarationTransformers, /*allowDtsFiles*/ false);
             if (length(declarationTransform.diagnostics)) {
@@ -615,6 +612,7 @@ namespace ts {
         getAllAccessorDeclarations: notImplemented,
         getSymbolOfExternalModuleSpecifier: notImplemented,
         isBindingCapturedByNode: notImplemented,
+        getDeclarationStatementsForSourceFile: notImplemented,
     };
 
     /*@internal*/

src/compiler/emitter.ts

@@ -2139,6 +2139,11 @@ namespace ts {
             : node;
     }
 
+    /* @internal */
+    export function createEmptyExports() {
+        return createExportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, createNamedExports([]), /*moduleSpecifier*/ undefined);
+    }
+
     export function createNamedExports(elements: ReadonlyArray<ExportSpecifier>) {
         const node = <NamedExports>createSynthesizedNode(SyntaxKind.NamedExports);
         node.elements = createNodeArray(elements);

src/compiler/factory.ts

@@ -2906,10 +2906,6 @@ namespace ts {
                 }
             }
 
-            if (!options.noEmit && options.allowJs && getEmitDeclarations(options)) {
-                createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_with_option_1, "allowJs", getEmitDeclarationOptionName(options));
-            }
-
             if (options.checkJs && !options.allowJs) {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1, "checkJs", "allowJs"));
             }

src/compiler/program.ts

@@ -1,11 +1,8 @@
 /*@internal*/
 namespace ts {
     export function getDeclarationDiagnostics(host: EmitHost, resolver: EmitResolver, file: SourceFile | undefined): DiagnosticWithLocation[] | undefined {
-        if (file && isSourceFileJS(file)) {
-            return []; // No declaration diagnostics for js for now
-        }
         const compilerOptions = host.getCompilerOptions();
-        const result = transformNodes(resolver, host, compilerOptions, file ? [file] : filter(host.getSourceFiles(), isSourceFileNotJS), [transformDeclarations], /*allowDtsFiles*/ false);
+        const result = transformNodes(resolver, host, compilerOptions, file ? [file] : host.getSourceFiles(), [transformDeclarations], /*allowDtsFiles*/ false);
         return result.diagnostics;
     }
 
@@ -190,15 +187,11 @@ namespace ts {
             }
         }
 
-        function createEmptyExports() {
-            return createExportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, createNamedExports([]), /*moduleSpecifier*/ undefined);
-        }
-
         function transformRoot(node: Bundle): Bundle;
         function transformRoot(node: SourceFile): SourceFile;
         function transformRoot(node: SourceFile | Bundle): SourceFile | Bundle;
         function transformRoot(node: SourceFile | Bundle) {
-            if (node.kind === SyntaxKind.SourceFile && (node.isDeclarationFile || isSourceFileJS(node))) {
+            if (node.kind === SyntaxKind.SourceFile && node.isDeclarationFile) {
                 return node;
             }
 
@@ -209,7 +202,10 @@ namespace ts {
                 let hasNoDefaultLib = false;
                 const bundle = createBundle(map(node.sourceFiles,
                     sourceFile => {
-                        if (sourceFile.isDeclarationFile || isSourceFileJS(sourceFile)) return undefined!; // Omit declaration files from bundle results, too // TODO: GH#18217
+                        if (sourceFile.isDeclarationFile) return undefined!; // Omit declaration files from bundle results, too // TODO: GH#18217
+                        if (isSourceFileJS(sourceFile)) {
+                            return updateSourceFileNode(sourceFile, resolver.getDeclarationStatementsForSourceFile(sourceFile, declarationEmitNodeBuilderFlags, symbolTracker) || emptyArray);
+                        }
                         hasNoDefaultLib = hasNoDefaultLib || sourceFile.hasNoDefaultLib;
                         currentSourceFile = sourceFile;
                         enclosingDeclaration = sourceFile;
@@ -257,6 +253,9 @@ namespace ts {
                 refs.forEach(referenceVisitor);
                 return bundle;
             }
+            else if (isSourceFileJS(node)) {
+                return updateSourceFileNode(node, resolver.getDeclarationStatementsForSourceFile(node, declarationEmitNodeBuilderFlags, symbolTracker) || emptyArray);
+            }
 
             // Single source file
             needsDeclare = true;
@@ -710,10 +709,6 @@ namespace ts {
             return isAnyImportOrReExport(result) || isExportAssignment(result) || hasModifier(result, ModifierFlags.Export);
         }
 
-        function needsScopeMarker(result: LateVisibilityPaintedStatement | ExportAssignment) {
-            return !isAnyImportOrReExport(result) && !isExportAssignment(result) && !hasModifier(result, ModifierFlags.Export) && !isAmbientModule(result);
-        }
-
         function visitDeclarationSubtree(input: Node): VisitResult<Node> {
             if (shouldStripInternal(input)) return;
             if (isDeclaration(input)) {

src/compiler/transformers/declarations.ts

@@ -3620,6 +3620,7 @@ namespace ts {
         getAllAccessorDeclarations(declaration: AccessorDeclaration): AllAccessorDeclarations;
         getSymbolOfExternalModuleSpecifier(node: StringLiteralLike): Symbol | undefined;
         isBindingCapturedByNode(node: Node, decl: VariableDeclaration | BindingElement): boolean;
+        getDeclarationStatementsForSourceFile(node: SourceFile, flags: NodeBuilderFlags, tracker: SymbolTracker): Statement[] | undefined;
     }
 
     export const enum SymbolFlags {
@@ -3700,6 +3701,12 @@ namespace ts {
 
         ClassMember = Method | Accessor | Property,
 
+        /* @internal */
+        ExportSupportsDefaultModifier = Class | Function | Interface,
+
+        /* @internal */
+        ExportDoesNotSupportDefaultModifier = ~ExportSupportsDefaultModifier,
+
         /* @internal */
         // The set of things we consider semantically classifiable.  Used to speed up the LS during
         // classification.

src/compiler/types.ts

@@ -2561,10 +2561,14 @@ namespace ts {
     }
 
     export function exportAssignmentIsAlias(node: ExportAssignment | BinaryExpression): boolean {
-        const e = isExportAssignment(node) ? node.expression : node.right;
+        const e = getExportAssignmentExpression(node);
         return isEntityNameExpression(e) || isClassExpression(e);
     }
 
+    export function getExportAssignmentExpression(node: ExportAssignment | BinaryExpression): Expression {
+        return isExportAssignment(node) ? node.expression : node.right;
+    }
+
     export function getEffectiveBaseTypeNode(node: ClassLikeDeclaration | InterfaceDeclaration) {
         const baseType = getClassExtendsHeritageElement(node);
         if (baseType && isInJSFile(node)) {
@@ -6656,6 +6660,21 @@ namespace ts {
         return false;
     }
 
+    /* @internal */
+    export function isScopeMarker(node: Node) {
+        return isExportAssignment(node) || isExportDeclaration(node);
+    }
+
+    /* @internal */
+    export function hasScopeMarker(statements: ReadonlyArray<Statement>) {
+        return some(statements, isScopeMarker);
+    }
+
+    /* @internal */
+    export function needsScopeMarker(result: Statement) {
+        return !isAnyImportOrReExport(result) && !isExportAssignment(result) && !hasModifier(result, ModifierFlags.Export) && !isAmbientModule(result);
+    }
+
     /* @internal */
     export function isForInOrOfStatement(node: Node): node is ForInOrOfStatement {
         return node.kind === SyntaxKind.ForInStatement || node.kind === SyntaxKind.ForOfStatement;

src/compiler/utilities.ts

@@ -219,14 +219,19 @@ namespace compiler {
             return vpath.changeExtension(path, ext);
         }
 
-        public getNumberOfJsFiles() {
-            let count = this.js.size;
-            this.js.forEach(document => {
-                if (ts.fileExtensionIs(document.file, ts.Extension.Json)) {
-                    count--;
-                }
-            });
-            return count;
+        public getNumberOfJsFiles(includeJson: boolean) {
+            if (includeJson) {
+                return this.js.size;
+            }
+            else {
+                let count = this.js.size;
+                this.js.forEach(document => {
+                    if (ts.fileExtensionIs(document.file, ts.Extension.Json)) {
+                        count--;
+                    }
+                });
+                return count;
+            }
         }
     }
 

src/harness/compiler.ts

@@ -883,7 +883,7 @@ namespace Harness {
                         throw new Error("Only declaration files should be generated when emitDeclarationOnly:true");
                     }
                 }
-                else if (result.dts.size !== result.getNumberOfJsFiles()) {
+                else if (result.dts.size !== result.getNumberOfJsFiles(/*includeJson*/ true)) {
                     throw new Error("There were no errors and declFiles generated did not match number of js files generated");
                 }
             }
@@ -902,7 +902,7 @@ namespace Harness {
                 if (vpath.isDeclaration(file.unitName) || vpath.isJson(file.unitName)) {
                     dtsFiles.push(file);
                 }
-                else if (vpath.isTypeScript(file.unitName)) {
+                else if (vpath.isTypeScript(file.unitName) || (vpath.isJavaScript(file.unitName) && options.allowJs)) {
                     const declFile = findResultCodeFile(file.unitName);
                     if (declFile && !findUnit(declFile.file, declInputFiles) && !findUnit(declFile.file, declOtherFiles)) {
                         dtsFiles.push({ unitName: declFile.file, content: utils.removeByteOrderMark(declFile.text) });
@@ -1267,7 +1267,7 @@ namespace Harness {
                 return;
             }
             else if (options.sourceMap || declMaps) {
-                if (result.maps.size !== (result.getNumberOfJsFiles() * (declMaps && options.sourceMap ? 2 : 1))) {
+                if (result.maps.size !== ((options.sourceMap ? result.getNumberOfJsFiles(/*includeJson*/ false) : 0) + (declMaps ? result.getNumberOfJsFiles(/*includeJson*/ true) : 0))) {
                     throw new Error("Number of sourcemap files should be same as js files.");
                 }
 

src/harness/harness.ts

@@ -47,7 +47,12 @@ namespace ts {
 
 export default hello.hello`);
             const allExpectedOutputs = ["/src/dist/src/index.js", "/src/dist/src/index.d.ts", "/src/dist/src/index.json"];
-            verifyProjectWithResolveJsonModuleWithFs(fs, "/src/tsconfig_withIncludeOfJson.json", allExpectedOutputs);
+            verifyProjectWithResolveJsonModuleWithFs(
+                fs,
+                "/src/tsconfig_withIncludeOfJson.json",
+                allExpectedOutputs,
+                [Diagnostics.Cannot_write_file_0_because_it_would_be_overwritten_by_multiple_input_files, "/src/dist/src/index.d.ts"]
+            );
         });
 
         it("with resolveJsonModule and files containing json file", () => {

src/testRunner/unittests/tsbuild/resolveJsonModule.ts

@@ -885,8 +885,8 @@ namespace ts.tscWatch {
                     // More comment`;
             const configFileContentAfterComment = `
                     "compilerOptions": {
-                        "allowJs": true,
-                        "declaration": true
+                        "inlineSourceMap": true,
+                        "mapRoot": "./"
                     }
                 }`;
             const configFileContentWithComment = configFileContentBeforeComment + configFileContentComment + configFileContentAfterComment;
@@ -900,8 +900,9 @@ namespace ts.tscWatch {
             const host = createWatchedSystem(files);
             const watch = createWatchOfConfigFile(configFile.path, host);
             const errors = () => [
-                getDiagnosticOfFile(watch().getCompilerOptions().configFile!, configFile.content.indexOf('"allowJs"'), '"allowJs"'.length, Diagnostics.Option_0_cannot_be_specified_with_option_1, "allowJs", "declaration"),
-                getDiagnosticOfFile(watch().getCompilerOptions().configFile!, configFile.content.indexOf('"declaration"'), '"declaration"'.length, Diagnostics.Option_0_cannot_be_specified_with_option_1, "allowJs", "declaration")
+                getDiagnosticOfFile(watch().getCompilerOptions().configFile!, configFile.content.indexOf('"inlineSourceMap"'), '"inlineSourceMap"'.length, Diagnostics.Option_0_cannot_be_specified_with_option_1, "mapRoot", "inlineSourceMap"),
+                getDiagnosticOfFile(watch().getCompilerOptions().configFile!, configFile.content.indexOf('"mapRoot"'), '"mapRoot"'.length, Diagnostics.Option_0_cannot_be_specified_with_option_1, "mapRoot", "inlineSourceMap"),
+                getDiagnosticOfFile(watch().getCompilerOptions().configFile!, configFile.content.indexOf('"mapRoot"'), '"mapRoot"'.length, Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1_or_option_2, "mapRoot", "sourceMap", "declarationMap")
             ];
             const intialErrors = errors();
             checkOutputErrorsInitial(host, intialErrors);

src/testRunner/unittests/tscWatch/programUpdates.ts

@@ -849,8 +849,8 @@ declare module '@custom/plugin' {
                 // comment`;
             const configFileContentAfterComment = `
                 "compilerOptions": {
-                    "allowJs": true,
-                    "declaration": true
+                    "inlineSourceMap": true,
+                    "mapRoot": "./"
                 }
             }`;
             const configFileContentWithComment = configFileContentBeforeComment + configFileContentComment + configFileContentAfterComment;
@@ -874,7 +874,7 @@ declare module '@custom/plugin' {
                 seq: 2,
                 arguments: { file: configFile.path, projectFileName: projectName, includeLinePosition: true }
             }).response as ReadonlyArray<server.protocol.DiagnosticWithLinePosition>;
-            assert.isTrue(diags.length === 2);
+            assert.isTrue(diags.length === 3);
 
             configFile.content = configFileContentWithoutCommentLine;
             host.reloadFS([file, configFile]);
@@ -885,10 +885,11 @@ declare module '@custom/plugin' {
                 seq: 2,
                 arguments: { file: configFile.path, projectFileName: projectName, includeLinePosition: true }
             }).response as ReadonlyArray<server.protocol.DiagnosticWithLinePosition>;
-            assert.isTrue(diagsAfterEdit.length === 2);
+            assert.isTrue(diagsAfterEdit.length === 3);
 
             verifyDiagnostic(diags[0], diagsAfterEdit[0]);
             verifyDiagnostic(diags[1], diagsAfterEdit[1]);
+            verifyDiagnostic(diags[2], diagsAfterEdit[2]);
 
             function verifyDiagnostic(beforeEditDiag: server.protocol.DiagnosticWithLinePosition, afterEditDiag: server.protocol.DiagnosticWithLinePosition) {
                 assert.equal(beforeEditDiag.message, afterEditDiag.message);