cts, mts, cjs, mjs, etc extension support

src/compiler/builder.ts

@@ -258,6 +258,14 @@ namespace ts {
             Debug.assert(!state.seenAffectedFiles || !state.seenAffectedFiles.size);
             state.seenAffectedFiles = state.seenAffectedFiles || new Set();
         }
+        if (useOldState) {
+            // Any time the interpretation of a source file changes, mark it as changed
+            forEachEntry(oldState!.fileInfos, (info, sourceFilePath) => {
+                if (state.fileInfos.has(sourceFilePath) && state.fileInfos.get(sourceFilePath)!.impliedFormat !== info.impliedFormat) {
+                    state.changedFilesSet.add(sourceFilePath);
+                }
+            });
+        }
 
         state.buildInfoEmitPending = !!state.changedFilesSet.size;
         return state;
@@ -744,13 +752,13 @@ namespace ts {
             const actualSignature = signature ?? value.signature;
             return value.version === actualSignature ?
                 value.affectsGlobalScope ?
-                    { version: value.version, signature: undefined, affectsGlobalScope: true } :
+                    { version: value.version, signature: undefined, affectsGlobalScope: true, impliedFormat: value.impliedFormat } :
                     value.version :
                 actualSignature !== undefined ?
                     signature === undefined ?
                         value :
-                        { version: value.version, signature, affectsGlobalScope: value.affectsGlobalScope } :
-                    { version: value.version, signature: false, affectsGlobalScope: value.affectsGlobalScope };
+                        { version: value.version, signature, affectsGlobalScope: value.affectsGlobalScope, impliedFormat: value.impliedFormat } :
+                    { version: value.version, signature: false, affectsGlobalScope: value.affectsGlobalScope, impliedFormat: value.impliedFormat };
         });
 
         let referencedMap: ProgramBuildInfoReferencedMap | undefined;
@@ -1243,10 +1251,10 @@ namespace ts {
 
     export function toBuilderStateFileInfo(fileInfo: ProgramBuildInfoFileInfo): BuilderState.FileInfo {
         return isString(fileInfo) ?
-            { version: fileInfo, signature: fileInfo, affectsGlobalScope: undefined } :
+            { version: fileInfo, signature: fileInfo, affectsGlobalScope: undefined, impliedFormat: undefined } :
             isString(fileInfo.signature) ?
                 fileInfo as BuilderState.FileInfo :
-                { version: fileInfo.version, signature: fileInfo.signature === false ? undefined : fileInfo.version, affectsGlobalScope: fileInfo.affectsGlobalScope };
+                { version: fileInfo.version, signature: fileInfo.signature === false ? undefined : fileInfo.version, affectsGlobalScope: fileInfo.affectsGlobalScope, impliedFormat: fileInfo.impliedFormat };
     }
 
     export function createBuildProgramUsingProgramBuildInfo(program: ProgramBuildInfo, buildInfoPath: string, host: ReadBuildProgramHost): EmitAndSemanticDiagnosticsBuilderProgram {

src/compiler/builderState.ts

@@ -82,6 +82,7 @@ namespace ts {
             readonly version: string;
             signature: string | undefined;
             affectsGlobalScope: boolean | undefined;
+            impliedFormat: number | undefined;
         }
 
         export interface ReadonlyManyToManyPathMap {
@@ -332,7 +333,7 @@ namespace ts {
                         }
                     }
                 }
-                fileInfos.set(sourceFile.resolvedPath, { version, signature: oldInfo && oldInfo.signature, affectsGlobalScope: isFileAffectingGlobalScope(sourceFile) || undefined });
+                fileInfos.set(sourceFile.resolvedPath, { version, signature: oldInfo && oldInfo.signature, affectsGlobalScope: isFileAffectingGlobalScope(sourceFile) || undefined, impliedFormat: sourceFile.impliedNodeFormat });
             }
 
             return {
@@ -433,7 +434,7 @@ namespace ts {
                 );
                 const firstDts = firstOrUndefined(emitOutput.outputFiles);
                 if (firstDts) {
-                    Debug.assert(fileExtensionIs(firstDts.name, Extension.Dts), "File extension for signature expected to be dts", () => `Found: ${getAnyExtensionFromPath(firstDts.name)} for ${firstDts.name}:: All output files: ${JSON.stringify(emitOutput.outputFiles.map(f => f.name))}`);
+                    Debug.assert(fileExtensionIsOneOf(firstDts.name, [Extension.Dts, Extension.Dmts, Extension.Dcts]), "File extension for signature expected to be dts", () => `Found: ${getAnyExtensionFromPath(firstDts.name)} for ${firstDts.name}:: All output files: ${JSON.stringify(emitOutput.outputFiles.map(f => f.name))}`);
                     latestSignature = (computeHash || generateDjb2Hash)(firstDts.text);
                     if (exportedModulesMapCache && latestSignature !== prevSignature) {
                         updateExportedModules(sourceFile, emitOutput.exportedModulesFromDeclarationEmit, exportedModulesMapCache);

src/compiler/checker.ts

@@ -30712,6 +30712,12 @@ namespace ts {
         }
 
         function checkAssertion(node: AssertionExpression) {
+            if (node.kind === SyntaxKind.TypeAssertionExpression) {
+                const file = getSourceFileOfNode(node);
+                if (file && fileExtensionIsOneOf(file.fileName, [Extension.Cts, Extension.Mts])) {
+                    grammarErrorOnNode(node, Diagnostics.This_syntax_is_reserved_in_files_with_the_mts_or_cts_extension_Use_an_as_expression_instead);
+                }
+            }
             return checkAssertionWorker(node, node.type, node.expression);
         }
 
@@ -42074,6 +42080,12 @@ namespace ts {
                 return false;
             }
 
+            if (node.typeParameters && !(length(node.typeParameters) > 1 || node.typeParameters.hasTrailingComma || node.typeParameters[0].constraint)) {
+                if (file && fileExtensionIsOneOf(file.fileName, [Extension.Mts, Extension.Cts])) {
+                    grammarErrorOnNode(node.typeParameters[0], Diagnostics.This_syntax_is_reserved_in_files_with_the_mts_or_cts_extension_Add_a_trailing_comma_or_explicit_constraint);
+                }
+            }
+
             const { equalsGreaterThanToken } = node;
             const startLine = getLineAndCharacterOfPosition(file, equalsGreaterThanToken.pos).line;
             const endLine = getLineAndCharacterOfPosition(file, equalsGreaterThanToken.end).line;

src/compiler/commandLineParser.ts

@@ -3218,7 +3218,7 @@ namespace ts {
         // Rather than re-query this for each file and filespec, we query the supported extensions
         // once and store it on the expansion context.
         const supportedExtensions = getSupportedExtensions(options, extraFileExtensions);
-        const supportedExtensionsWithJsonIfResolveJsonModule = getSuppoertedExtensionsWithJsonIfResolveJsonModule(options, supportedExtensions);
+        const supportedExtensionsWithJsonIfResolveJsonModule = getSupportedExtensionsWithJsonIfResolveJsonModule(options, supportedExtensions);
 
         // Literal files are always included verbatim. An "include" or "exclude" specification cannot
         // remove a literal file.
@@ -3231,7 +3231,7 @@ namespace ts {
 
         let jsonOnlyIncludeRegexes: readonly RegExp[] | undefined;
         if (validatedIncludeSpecs && validatedIncludeSpecs.length > 0) {
-            for (const file of host.readDirectory(basePath, supportedExtensionsWithJsonIfResolveJsonModule, validatedExcludeSpecs, validatedIncludeSpecs, /*depth*/ undefined)) {
+            for (const file of host.readDirectory(basePath, flatten(supportedExtensionsWithJsonIfResolveJsonModule), validatedExcludeSpecs, validatedIncludeSpecs, /*depth*/ undefined)) {
                 if (fileExtensionIs(file, Extension.Json)) {
                     // Valid only if *.json specified
                     if (!jsonOnlyIncludeRegexes) {
@@ -3456,16 +3456,24 @@ namespace ts {
      * extension priority.
      *
      * @param file The path to the file.
-     * @param extensionPriority The priority of the extension.
-     * @param context The expansion context.
      */
-    function hasFileWithHigherPriorityExtension(file: string, literalFiles: ESMap<string, string>, wildcardFiles: ESMap<string, string>, extensions: readonly string[], keyMapper: (value: string) => string) {
-        const extensionPriority = getExtensionPriority(file, extensions);
-        const adjustedExtensionPriority = adjustExtensionPriority(extensionPriority, extensions);
-        for (let i = ExtensionPriority.Highest; i < adjustedExtensionPriority; i++) {
-            const higherPriorityExtension = extensions[i];
-            const higherPriorityPath = keyMapper(changeExtension(file, higherPriorityExtension));
+    function hasFileWithHigherPriorityExtension(file: string, literalFiles: ESMap<string, string>, wildcardFiles: ESMap<string, string>, extensions: readonly string[][], keyMapper: (value: string) => string) {
+        const extensionGroup = forEach(extensions, group => fileExtensionIsOneOf(file, group) ? group : undefined);
+        if (!extensionGroup) {
+            return false;
+        }
+        for (const ext of extensionGroup) {
+            if (fileExtensionIs(file, ext)) {
+                return false;
+            }
+            const higherPriorityPath = keyMapper(changeExtension(file, ext));
             if (literalFiles.has(higherPriorityPath) || wildcardFiles.has(higherPriorityPath)) {
+                if (ext === Extension.Dts && (fileExtensionIs(file, Extension.Js) || fileExtensionIs(file, Extension.Jsx))) {
+                    // LEGACY BEHAVIOR: An off-by-one bug somewhere in the extension priority system for wildcard module loading allowed declaration
+                    // files to be loaded alongside their js(x) counterparts. We regard this as generally undesirable, but retain the behavior to
+                    // prevent breakage.
+                    continue;
+                }
                 return true;
             }
         }
@@ -3478,15 +3486,18 @@ namespace ts {
      * already been included.
      *
      * @param file The path to the file.
-     * @param extensionPriority The priority of the extension.
-     * @param context The expansion context.
      */
-    function removeWildcardFilesWithLowerPriorityExtension(file: string, wildcardFiles: ESMap<string, string>, extensions: readonly string[], keyMapper: (value: string) => string) {
-        const extensionPriority = getExtensionPriority(file, extensions);
-        const nextExtensionPriority = getNextLowestExtensionPriority(extensionPriority, extensions);
-        for (let i = nextExtensionPriority; i < extensions.length; i++) {
-            const lowerPriorityExtension = extensions[i];
-            const lowerPriorityPath = keyMapper(changeExtension(file, lowerPriorityExtension));
+    function removeWildcardFilesWithLowerPriorityExtension(file: string, wildcardFiles: ESMap<string, string>, extensions: readonly string[][], keyMapper: (value: string) => string) {
+        const extensionGroup = forEach(extensions, group => fileExtensionIsOneOf(file, group) ? group : undefined);
+        if (!extensionGroup) {
+            return;
+        }
+        for (let i = extensionGroup.length - 1; i >= 0; i--) {
+            const ext = extensionGroup[i];
+            if (fileExtensionIs(file, ext)) {
+                return;
+            }
+            const lowerPriorityPath = keyMapper(changeExtension(file, ext));
             wildcardFiles.delete(lowerPriorityPath);
         }
     }

src/compiler/diagnosticMessages.json

@@ -5909,6 +5909,14 @@
         "category": "Error",
         "code": 7058
     },
+    "This syntax is reserved in files with the .mts or .cts extension. Use an `as` expression instead.": {
+        "category": "Error",
+        "code": 7059
+    },
+    "This syntax is reserved in files with the .mts or .cts extension. Add a trailing comma or explicit constraint.": {
+        "category": "Error",
+        "code": 7060
+    },
 
 
     "You cannot rename this element.": {

src/compiler/emitter.ts

@@ -89,7 +89,7 @@ namespace ts {
             return getOutputPathsForBundle(options, forceDtsPaths);
         }
         else {
-            const ownOutputFilePath = getOwnEmitOutputFilePath(sourceFile.fileName, host, getOutputExtension(sourceFile, options));
+            const ownOutputFilePath = getOwnEmitOutputFilePath(sourceFile.fileName, host, getOutputExtension(sourceFile.fileName, options));
             const isJsonFile = isJsonSourceFile(sourceFile);
             // If json file emits to the same location skip writing it, if emitDeclarationOnly skip writing it
             const isJsonEmittedToSameLocation = isJsonFile &&
@@ -106,27 +106,13 @@ namespace ts {
         return (options.sourceMap && !options.inlineSourceMap) ? jsFilePath + ".map" : undefined;
     }
 
-    // JavaScript files are always LanguageVariant.JSX, as JSX syntax is allowed in .js files also.
-    // So for JavaScript files, '.jsx' is only emitted if the input was '.jsx', and JsxEmit.Preserve.
-    // For TypeScript, the only time to emit with a '.jsx' extension, is on JSX input, and JsxEmit.Preserve
     /* @internal */
-    export function getOutputExtension(sourceFile: SourceFile, options: CompilerOptions): Extension {
-        if (isJsonSourceFile(sourceFile)) {
-            return Extension.Json;
-        }
-
-        if (options.jsx === JsxEmit.Preserve) {
-            if (isSourceFileJS(sourceFile)) {
-                if (fileExtensionIs(sourceFile.fileName, Extension.Jsx)) {
-                    return Extension.Jsx;
-                }
-            }
-            else if (sourceFile.languageVariant === LanguageVariant.JSX) {
-                // TypeScript source file preserving JSX syntax
-                return Extension.Jsx;
-            }
-        }
-        return Extension.Js;
+    export function getOutputExtension(fileName: string, options: CompilerOptions): Extension {
+        return fileExtensionIs(fileName, Extension.Json) ? Extension.Json :
+        options.jsx === JsxEmit.Preserve && fileExtensionIsOneOf(fileName, [Extension.Jsx, Extension.Tsx]) ? Extension.Jsx :
+        fileExtensionIsOneOf(fileName, [Extension.Mts, Extension.Mjs]) ? Extension.Mjs :
+        fileExtensionIsOneOf(fileName, [Extension.Cts, Extension.Cjs]) ? Extension.Cjs :
+        Extension.Js;
     }
 
     function getOutputPathWithoutChangingExt(inputFileName: string, configFile: ParsedCommandLine, ignoreCase: boolean, outputDir: string | undefined, getCommonSourceDirectory?: () => string) {
@@ -140,10 +126,9 @@ namespace ts {
 
     /* @internal */
     export function getOutputDeclarationFileName(inputFileName: string, configFile: ParsedCommandLine, ignoreCase: boolean, getCommonSourceDirectory?: () => string) {
-        Debug.assert(!fileExtensionIs(inputFileName, Extension.Dts) && !fileExtensionIs(inputFileName, Extension.Json));
         return changeExtension(
             getOutputPathWithoutChangingExt(inputFileName, configFile, ignoreCase, configFile.options.declarationDir || configFile.options.outDir, getCommonSourceDirectory),
-            Extension.Dts
+            getDeclarationEmitExtensionForPath(inputFileName)
         );
     }
 
@@ -152,11 +137,7 @@ namespace ts {
         const isJsonFile = fileExtensionIs(inputFileName, Extension.Json);
         const outputFileName = changeExtension(
             getOutputPathWithoutChangingExt(inputFileName, configFile, ignoreCase, configFile.options.outDir, getCommonSourceDirectory),
-            isJsonFile ?
-                Extension.Json :
-                configFile.options.jsx === JsxEmit.Preserve && (fileExtensionIs(inputFileName, Extension.Tsx) || fileExtensionIs(inputFileName, Extension.Jsx)) ?
-                    Extension.Jsx :
-                    Extension.Js
+            getOutputExtension(inputFileName, configFile.options)
         );
         return !isJsonFile || comparePaths(inputFileName, outputFileName, Debug.checkDefined(configFile.options.configFilePath), ignoreCase) !== Comparison.EqualTo ?
             outputFileName :
@@ -238,7 +219,7 @@ namespace ts {
     export function getCommonSourceDirectoryOfConfig({ options, fileNames }: ParsedCommandLine, ignoreCase: boolean): string {
         return getCommonSourceDirectory(
             options,
-            () => filter(fileNames, file => !(options.noEmitForJsFiles && fileExtensionIsOneOf(file, supportedJSExtensions)) && !fileExtensionIs(file, Extension.Dts)),
+            () => filter(fileNames, file => !(options.noEmitForJsFiles && fileExtensionIsOneOf(file, supportedJSExtensionsFlat)) && !fileExtensionIs(file, Extension.Dts)),
             getDirectoryPath(normalizeSlashes(Debug.checkDefined(options.configFilePath))),
             createGetCanonicalFileName(!ignoreCase)
         );