Move json declaration file emit behind a experimentalJsonDeclarationEmit flag

src/compiler/commandLineParser.ts

@@ -686,6 +686,13 @@ namespace ts {
             category: Diagnostics.Experimental_Options,
             description: Diagnostics.Enables_experimental_support_for_emitting_type_metadata_for_decorators
         },
+        {
+            name: "experimentalJsonDeclarationEmit",
+            type: "boolean",
+            category: Diagnostics.Advanced_Options, // Under "advanced options" so it's hidden from --init
+            description: Diagnostics.Enables_experimental_declaration_emit_for_json_files,
+            affectsEmit: true,
+        },
 
         // Advanced
         {

src/compiler/diagnosticMessages.json

@@ -4140,6 +4140,10 @@
         "category": "Message",
         "code": 6223
     },
+    "Enables experimental declaration emit for json files.": {
+        "category": "Message",
+        "code": 6224
+    },
 
     "Projects to reference": {
         "category": "Message",

src/compiler/emitter.ts

@@ -142,9 +142,20 @@ namespace ts {
             inputFileName;
     }
 
+    /* @internal */
+    export function hasDeclarationFileOutput(filename: string, options: CompilerOptions) {
+        if (fileExtensionIs(filename, Extension.Json) && !options.experimentalJsonDeclarationEmit) {
+            return false;
+        }
+        return true;
+    }
+
     /* @internal */
     export function getOutputDeclarationFileName(inputFileName: string, configFile: ParsedCommandLine, ignoreCase: boolean) {
         Debug.assert(!fileExtensionIs(inputFileName, Extension.Dts));
+        if (!hasDeclarationFileOutput(inputFileName, configFile.options)) {
+            return undefined;
+        }
         return changeExtension(
             getOutputPathWithoutChangingExt(inputFileName, configFile, ignoreCase, configFile.options.declarationDir || configFile.options.outDir),
             Extension.Dts
@@ -247,7 +258,10 @@ namespace ts {
             if (jsFilePath) return jsFilePath;
             if (fileExtensionIs(inputFileName, Extension.Json)) continue;
             if (getEmitDeclarations(configFile.options)) {
-                return getOutputDeclarationFileName(inputFileName, configFile, ignoreCase);
+                const result = getOutputDeclarationFileName(inputFileName, configFile, ignoreCase);
+                if (result) {
+                    return result;
+                }
             }
         }
         const buildInfoPath = getTsBuildInfoEmitOutputFilePath(configFile.options);

src/compiler/program.ts

@@ -855,7 +855,10 @@ namespace ts {
                             else if (getEmitModuleKind(parsedRef.commandLine.options) === ModuleKind.None) {
                                 for (const fileName of parsedRef.commandLine.fileNames) {
                                     if (!fileExtensionIs(fileName, Extension.Dts)) {
-                                        processSourceFile(getOutputDeclarationFileName(fileName, parsedRef.commandLine, !host.useCaseSensitiveFileNames()), /*isDefaultLib*/ false, /*ignoreNoDefaultLib*/ false, /*packageId*/ undefined);
+                                        const outputPath = getOutputDeclarationFileName(fileName, parsedRef.commandLine, !host.useCaseSensitiveFileNames());
+                                        if (outputPath) {
+                                            processSourceFile(outputPath, /*isDefaultLib*/ false, /*ignoreNoDefaultLib*/ false, /*packageId*/ undefined);
+                                        }
                                     }
                                 }
                             }
@@ -1434,7 +1437,9 @@ namespace ts {
                     const redirectProject = getProjectReferenceRedirectProject(newSourceFile.fileName);
                     if (redirectProject && !(redirectProject.commandLine.options.outFile || redirectProject.commandLine.options.out)) {
                         const redirect = getProjectReferenceOutputName(redirectProject, newSourceFile.fileName);
-                        addFileToFilesByName(newSourceFile, toPath(redirect), /*redirectedPath*/ undefined);
+                        if (redirect) {
+                            addFileToFilesByName(newSourceFile, toPath(redirect), /*redirectedPath*/ undefined);
+                        }
                     }
                 }
                 // Set the file as found during node modules search if it was found that way in old progra,
@@ -2356,13 +2361,15 @@ namespace ts {
                         return undefined;
                     }
                     const redirect = getProjectReferenceOutputName(redirectProject, fileName);
-                    fileName = redirect;
-                    // Once we start redirecting to a file, we can potentially come back to it
-                    // via a back-reference from another file in the .d.ts folder. If that happens we'll
-                    // end up trying to add it to the program *again* because we were tracking it via its
-                    // original (un-redirected) name. So we have to map both the original path and the redirected path
-                    // to the source file we're about to find/create
-                    redirectedPath = toPath(redirect);
+                    if (redirect) {
+                        fileName = redirect;
+                        // Once we start redirecting to a file, we can potentially come back to it
+                        // via a back-reference from another file in the .d.ts folder. If that happens we'll
+                        // end up trying to add it to the program *again* because we were tracking it via its
+                        // original (un-redirected) name. So we have to map both the original path and the redirected path
+                        // to the source file we're about to find/create
+                        redirectedPath = toPath(redirect);
+                    }
                 }
             }
 
@@ -2533,7 +2540,9 @@ namespace ts {
                             forEach(resolvedRef.commandLine.fileNames, fileName => {
                                 if (!fileExtensionIs(fileName, Extension.Dts)) {
                                     const outputDts = getOutputDeclarationFileName(fileName, resolvedRef.commandLine, host.useCaseSensitiveFileNames());
-                                    mapFromToProjectReferenceRedirectSource!.set(toPath(outputDts), fileName);
+                                    if (outputDts) {
+                                        mapFromToProjectReferenceRedirectSource!.set(toPath(outputDts), fileName);
+                                    }
                                 }
                             });
                         }

src/compiler/transformers/declarations.ts

@@ -2,7 +2,7 @@
 namespace ts {
     export function getDeclarationDiagnostics(host: EmitHost, resolver: EmitResolver, file: SourceFile | undefined): DiagnosticWithLocation[] | undefined {
         const compilerOptions = host.getCompilerOptions();
-        const result = transformNodes(resolver, host, compilerOptions, file ? [file] : host.getSourceFiles(), [transformDeclarations], /*allowDtsFiles*/ false);
+        const result = transformNodes(resolver, host, compilerOptions, filter(file ? [file] : host.getSourceFiles(), f => !!getOutputPathsFor(f, host, /*forcedtsPaths*/ false).declarationFilePath), [transformDeclarations], /*allowDtsFiles*/ false);
         return result.diagnostics;
     }
 

src/compiler/types.ts

@@ -5029,6 +5029,7 @@ namespace ts {
         esModuleInterop?: boolean;
         /* @internal */ showConfig?: boolean;
         useDefineForClassFields?: boolean;
+        /* @internal */ experimentalJsonDeclarationEmit?: boolean;
 
         [option: string]: CompilerOptionsValue | TsConfigSourceFile | undefined;
     }

src/compiler/utilities.ts

@@ -3633,7 +3633,10 @@ namespace ts {
         return getDeclarationEmitOutputFilePathWorker(fileName, host.getCompilerOptions(), host.getCurrentDirectory(), host.getCommonSourceDirectory(), f => host.getCanonicalFileName(f));
     }
 
-    export function getDeclarationEmitOutputFilePathWorker(fileName: string, options: CompilerOptions, currentDirectory: string, commonSourceDirectory: string, getCanonicalFileName: GetCanonicalFileName): string {
+    export function getDeclarationEmitOutputFilePathWorker(fileName: string, options: CompilerOptions, currentDirectory: string, commonSourceDirectory: string, getCanonicalFileName: GetCanonicalFileName): string | undefined {
+        if (!hasDeclarationFileOutput(fileName, options)) {
+            return undefined;
+        }
         const outputDir = options.declarationDir || options.outDir; // Prefer declaration folder if specified
 
         const path = outputDir

src/harness/harness.ts

@@ -888,7 +888,7 @@ namespace Harness {
                         throw new Error("Only declaration files should be generated when emitDeclarationOnly:true");
                     }
                 }
-                else if (result.dts.size !== result.getNumberOfJsFiles(/*includeJson*/ true)) {
+                else if (result.dts.size !== result.getNumberOfJsFiles(ts.hasDeclarationFileOutput("/foo.json", options))) {
                     throw new Error("There were no errors and declFiles generated did not match number of js files generated");
                 }
             }

src/server/project.ts

@@ -1219,8 +1219,8 @@ namespace ts.server {
             };
         }
 
-        private isValidGeneratedFileWatcher(generateFile: string, watcher: GeneratedFileWatcher) {
-            return this.toPath(generateFile) === watcher.generatedFilePath;
+        private isValidGeneratedFileWatcher(generateFile: string | undefined, watcher: GeneratedFileWatcher) {
+            return generateFile !== undefined && this.toPath(generateFile) === watcher.generatedFilePath;
         }
 
         private clearGeneratedFileWatch() {

src/testRunner/unittests/tsbuild/javascriptProjectEmit.ts

@@ -276,7 +276,8 @@ namespace ts {
                             "checkJs": true,
                             "resolveJsonModule": true,
                             "esModuleInterop": true,
-                            "declaration": true
+                            "declaration": true,
+                            "experimentalJsonDeclarationEmit": true
                         }
                     }`,
             }, symbolLibContent),

tests/baselines/reference/showConfig/Shows tsconfig for single option/experimentalJsonDeclarationEmit/tsconfig.json

@@ -0,0 +1,5 @@
+{
+    "compilerOptions": {
+        "experimentalJsonDeclarationEmit": true
+    }
+}

tests/baselines/reference/tsbuild/javascriptProjectEmit/initial-build/loads-js-based-projects-with-non-moved-json-files-and-emits-them-correctly.js

@@ -48,6 +48,7 @@ exports.m = common_1["default"];
       "resolveJsonModule": true,
       "esModuleInterop": true,
       "declaration": true,
+      "experimentalJsonDeclarationEmit": true,
       "composite": true,
       "configFilePath": "../../src/sub-project/tsconfig.json"
     },
@@ -127,6 +128,7 @@ exports.getVar = getVar;
       "resolveJsonModule": true,
       "esModuleInterop": true,
       "declaration": true,
+      "experimentalJsonDeclarationEmit": true,
       "composite": true,
       "configFilePath": "../../src/sub-project-2/tsconfig.json"
     },
@@ -204,6 +206,7 @@ export declare const val: number;
       "resolveJsonModule": true,
       "esModuleInterop": true,
       "declaration": true,
+      "experimentalJsonDeclarationEmit": true,
       "composite": true,
       "configFilePath": "./tsconfig.json"
     },

tests/baselines/reference/tsbuild/resolveJsonModule/initial-build/files-containing-json-file.js

@@ -54,6 +54,7 @@ exports["default"] = hello_json_1["default"].hello;
       "allowSyntheticDefaultImports": true,
       "outDir": "./",
       "skipDefaultLibCheck": true,
+      "experimentalJsonDeclarationEmit": true,
       "configFilePath": "../tsconfig_withFiles.json"
     },
     "referencedMap": {

tests/baselines/reference/tsbuild/resolveJsonModule/initial-build/importing-json-module-from-project-reference.js

@@ -52,6 +52,7 @@ console.log(foo_json_1.foo);
       "resolveJsonModule": true,
       "strict": true,
       "esModuleInterop": true,
+      "experimentalJsonDeclarationEmit": true,
       "configFilePath": "./tsconfig.json"
     },
     "referencedMap": {
@@ -94,6 +95,7 @@ export declare const foo: string;
       "resolveJsonModule": true,
       "strict": true,
       "esModuleInterop": true,
+      "experimentalJsonDeclarationEmit": true,
       "configFilePath": "./tsconfig.json"
     },
     "referencedMap": {},

tests/baselines/reference/tsbuild/resolveJsonModule/initial-build/include-and-files.js

@@ -54,6 +54,7 @@ exports["default"] = hello_json_1["default"].hello;
       "allowSyntheticDefaultImports": true,
       "outDir": "./",
       "skipDefaultLibCheck": true,
+      "experimentalJsonDeclarationEmit": true,
       "configFilePath": "../tsconfig_withIncludeAndFiles.json"
     },
     "referencedMap": {

tests/baselines/reference/tsbuild/resolveJsonModule/initial-build/include-of-json-along-with-other-include.js

@@ -54,6 +54,7 @@ exports["default"] = hello_json_1["default"].hello;
       "allowSyntheticDefaultImports": true,
       "outDir": "./",
       "skipDefaultLibCheck": true,
+      "experimentalJsonDeclarationEmit": true,
       "configFilePath": "../tsconfig_withIncludeOfJson.json"
     },
     "referencedMap": {

tests/baselines/reference/tsbuild/resolveJsonModule/initial-build/sourcemap.js

@@ -65,6 +65,7 @@ exports["default"] = hello_json_1["default"].hello;
       "allowSyntheticDefaultImports": true,
       "outDir": "./",
       "skipDefaultLibCheck": true,
+      "experimentalJsonDeclarationEmit": true,
       "configFilePath": "../tsconfig_withFiles.json"
     },
     "referencedMap": {
@@ -92,7 +93,8 @@ exports["default"] = hello_json_1["default"].hello;
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
     "outDir": "dist",
-    "skipDefaultLibCheck": true
+    "skipDefaultLibCheck": true,
+    "experimentalJsonDeclarationEmit": true
   },
   "files": [
     "src/index.ts", "src/hello.json"

tests/baselines/reference/tsbuild/resolveJsonModule/initial-build/without-outDir.js

@@ -39,7 +39,8 @@ exports["default"] = hello_json_1["default"].hello;
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
 
-    "skipDefaultLibCheck": true
+    "skipDefaultLibCheck": true,
+    "experimentalJsonDeclarationEmit": true
   },
   "files": [
     "src/index.ts", "src/hello.json"
@@ -71,6 +72,7 @@ exports["default"] = hello_json_1["default"].hello;
       "esModuleInterop": true,
       "allowSyntheticDefaultImports": true,
       "skipDefaultLibCheck": true,
+      "experimentalJsonDeclarationEmit": true,
       "configFilePath": "./tsconfig_withFiles.json"
     },
     "referencedMap": {

tests/cases/compiler/requireOfJsonFileTypes.ts

@@ -5,6 +5,7 @@
 // @fullEmitPaths: true
 // @resolveJsonModule: true
 // @declaration: true
+// @experimentalJsonDeclarationEmit: true
 
 // @Filename: file1.ts
 import b = require('./b.json');

tests/cases/compiler/requireOfJsonFileWithDeclaration.ts

@@ -3,6 +3,7 @@
 // @fullEmitPaths: true
 // @resolveJsonModule: true
 // @declaration: true
+// @experimentalJsonDeclarationEmit: true
 
 // @Filename: file1.ts
 import b1 = require('./b.json');

tests/cases/conformance/jsdoc/declarations/jsDeclarationsJson.ts

@@ -4,6 +4,7 @@
 // @resolveJsonModule: true
 // @outDir: ./out
 // @declaration: true
+// @experimentalJsonDeclarationEmit: true
 // @filename: index.js
 const j = require("./obj.json");
 module.exports = j;

tests/cases/conformance/jsdoc/declarations/jsDeclarationsPackageJson.ts

@@ -4,6 +4,7 @@
 // @resolveJsonModule: true
 // @outDir: ./out
 // @declaration: true
+// @experimentalJsonDeclarationEmit: true
 // @filename: index.js
 const j = require("./package.json");
 module.exports = j;

tests/projects/importJsonFromProjectReference/tsconfig.json

@@ -6,7 +6,8 @@
         "composite": true,
         "resolveJsonModule": true,
         "strict": true,
-        "esModuleInterop": true
+        "esModuleInterop": true,
+        "experimentalJsonDeclarationEmit": true
     },
     "references": [
         {

tests/projects/resolveJsonModuleAndComposite/tsconfig_withFiles.json

@@ -7,7 +7,8 @@
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
     "outDir": "dist",
-    "skipDefaultLibCheck": true
+    "skipDefaultLibCheck": true,
+    "experimentalJsonDeclarationEmit": true
   },
   "files": [
     "src/index.ts", "src/hello.json"

tests/projects/resolveJsonModuleAndComposite/tsconfig_withInclude.json

@@ -7,7 +7,8 @@
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
     "outDir": "dist",
-    "skipDefaultLibCheck": true
+    "skipDefaultLibCheck": true,
+    "experimentalJsonDeclarationEmit": true
   },
   "include": [
     "src/**/*"

tests/projects/resolveJsonModuleAndComposite/tsconfig_withIncludeAndFiles.json

@@ -7,7 +7,8 @@
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
     "outDir": "dist",
-    "skipDefaultLibCheck": true
+    "skipDefaultLibCheck": true,
+    "experimentalJsonDeclarationEmit": true
   },
   "files": [
     "src/hello.json"

tests/projects/resolveJsonModuleAndComposite/tsconfig_withIncludeOfJson.json

@@ -7,7 +7,8 @@
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,
     "outDir": "dist",
-    "skipDefaultLibCheck": true
+    "skipDefaultLibCheck": true,
+    "experimentalJsonDeclarationEmit": true
   },
   "include": [
     "src/**/*", "src/**/*.json"