[v22.x backport] module: add module.stripTypeScriptTypes

doc/api/cli.md

@@ -1042,7 +1042,7 @@ Use this flag to enable [ShadowRealm][] support.
 added: v22.6.0
 -->
 
-> Stability: 1.0 - Early development
+> Stability: 1.1 - Active development
 
 Enable experimental type-stripping for TypeScript files.
 For more information, see the [TypeScript type-stripping][] documentation.
@@ -1096,7 +1096,7 @@ Enable module mocking in the test runner.
 added: v22.7.0
 -->
 
-> Stability: 1.0 - Early development
+> Stability: 1.1 - Active development
 
 Enables the transformation of TypeScript-only syntax into JavaScript code.
 Implies `--experimental-strip-types` and `--enable-source-maps`.

doc/api/module.md

@@ -352,6 +352,105 @@ changes:
 Register a module that exports [hooks][] that customize Node.js module
 resolution and loading behavior. See [Customization hooks][].
 
+## `module.stripTypeScriptTypes(code[, options])`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1.1 - Active development
+
+* `code` {string} The code to strip type annotations from.
+* `options` {Object}
+  * `mode` {string} **Default:** `'strip'`. Possible values are:
+    * `'strip'` Only strip type annotations without performing the transformation of TypeScript features.
+    * `'transform'` Strip type annotations and transform TypeScript features to JavaScript.
+  * `sourceMap` {boolean} **Default:** `false`. Only when `mode` is `'transform'`, if `true`, a source map
+    will be generated for the transformed code.
+  * `sourceUrl` {string}  Specifies the source url used in the source map.
+* Returns: {string} The code with type annotations stripped.
+  `module.stripTypeScriptTypes()` removes type annotations from TypeScript code. It
+  can be used to strip type annotations from TypeScript code before running it
+  with `vm.runInContext()` or `vm.compileFunction()`.
+  By default, it will throw an error if the code contains TypeScript features
+  that require transformation such as `Enums`,
+  see [type-stripping][] for more information.
+  When mode is `'transform'`, it also transforms TypeScript features to JavaScript,
+  see [transform TypeScript features][] for more information.
+  When mode is `'strip'`, source maps are not generated, because locations are preserved.
+  If `sourceMap` is provided, when mode is `'strip'`, an error will be thrown.
+
+_WARNING_: The output of this function should not be considered stable across Node.js versions,
+due to changes in the TypeScript parser.
+
+```mjs
+import { stripTypeScriptTypes } from 'node:module';
+const code = 'const a: number = 1;';
+const strippedCode = stripTypeScriptTypes(code);
+console.log(strippedCode);
+// Prints: const a         = 1;
+```
+
+```cjs
+const { stripTypeScriptTypes } = require('node:module');
+const code = 'const a: number = 1;';
+const strippedCode = stripTypeScriptTypes(code);
+console.log(strippedCode);
+// Prints: const a         = 1;
+```
+
+If `sourceUrl` is provided, it will be used appended as a comment at the end of the output:
+
+```mjs
+import { stripTypeScriptTypes } from 'node:module';
+const code = 'const a: number = 1;';
+const strippedCode = stripTypeScriptTypes(code, { mode: 'strip', sourceUrl: 'source.ts' });
+console.log(strippedCode);
+// Prints: const a         = 1\n\n//# sourceURL=source.ts;
+```
+
+```cjs
+const { stripTypeScriptTypes } = require('node:module');
+const code = 'const a: number = 1;';
+const strippedCode = stripTypeScriptTypes(code, { mode: 'strip', sourceUrl: 'source.ts' });
+console.log(strippedCode);
+// Prints: const a         = 1\n\n//# sourceURL=source.ts;
+```
+
+When `mode` is `'transform'`, the code is transformed to JavaScript:
+
+```mjs
+import { stripTypeScriptTypes } from 'node:module';
+const code = `
+  namespace MathUtil {
+    export const add = (a: number, b: number) => a + b;
+  }`;
+const strippedCode = stripTypeScriptTypes(code, { mode: 'transform', sourceMap: true });
+console.log(strippedCode);
+// Prints:
+// var MathUtil;
+// (function(MathUtil) {
+//     MathUtil.add = (a, b)=>a + b;
+// })(MathUtil || (MathUtil = {}));
+// # sourceMappingURL=data:application/json;base64, ...
+```
+
+```cjs
+const { stripTypeScriptTypes } = require('node:module');
+const code = `
+  namespace MathUtil {
+    export const add = (a: number, b: number) => a + b;
+  }`;
+const strippedCode = stripTypeScriptTypes(code, { mode: 'transform', sourceMap: true });
+console.log(strippedCode);
+// Prints:
+// var MathUtil;
+// (function(MathUtil) {
+//     MathUtil.add = (a, b)=>a + b;
+// })(MathUtil || (MathUtil = {}));
+// # sourceMappingURL=data:application/json;base64, ...
+```
+
 ### `module.syncBuiltinESMExports()`
 
 <!-- YAML
@@ -1333,3 +1432,5 @@ returned object contains the following keys:
 [realm]: https://tc39.es/ecma262/#realm
 [source map include directives]: https://sourcemaps.info/spec.html#h.lmz475t4mvbx
 [transferrable objects]: worker_threads.md#portpostmessagevalue-transferlist
+[transform TypeScript features]: typescript.md#typescript-features
+[type-stripping]: typescript.md#type-stripping

doc/api/process.md

@@ -2009,7 +2009,7 @@ This value is therefore identical to that of `process.features.tls`.
 added: v22.10.0
 -->
 
-> Stability: 1.0 - Early development
+> Stability: 1.1 - Active development
 
 * {boolean|string}
 

doc/api/typescript.md

@@ -7,7 +7,7 @@ changes:
     description: Added `--experimental-transform-types` flag.
 -->
 
-> Stability: 1.0 - Early development
+> Stability: 1.1 - Active development
 
 ## Enabling
 
@@ -50,7 +50,7 @@ To use TypeScript with full support for all TypeScript features, including
 added: v22.6.0
 -->
 
-> Stability: 1.0 - Early development
+> Stability: 1.1 - Active development
 
 The flag [`--experimental-strip-types`][] enables Node.js to run TypeScript
 files. By default Node.js will execute only files that contain no

lib/internal/main/eval_string.js

@@ -14,8 +14,8 @@ const {
   markBootstrapComplete,
 } = require('internal/process/pre_execution');
 const { evalModuleEntryPoint, evalScript } = require('internal/process/execution');
-const { addBuiltinLibsToObject, stripTypeScriptTypes } = require('internal/modules/helpers');
-
+const { addBuiltinLibsToObject } = require('internal/modules/helpers');
+const { stripTypeScriptModuleTypes } = require('internal/modules/typescript');
 const { getOptionValue } = require('internal/options');
 
 prepareMainThreadExecution();
@@ -24,7 +24,7 @@ markBootstrapComplete();
 
 const code = getOptionValue('--eval');
 const source = getOptionValue('--experimental-strip-types') ?
-  stripTypeScriptTypes(code) :
+  stripTypeScriptModuleTypes(code) :
   code;
 
 const print = getOptionValue('--print');

lib/internal/modules/cjs/loader.js

@@ -125,10 +125,10 @@ const { pathToFileURL, fileURLToPath, isURL } = require('internal/url');
 const {
   pendingDeprecate,
   emitExperimentalWarning,
-  isUnderNodeModules,
   kEmptyObject,
   setOwnProperty,
   getLazy,
+  isUnderNodeModules,
   isWindows,
 } = require('internal/util');
 const {
@@ -153,8 +153,8 @@ const {
   setHasStartedUserCJSExecution,
   stripBOM,
   toRealPath,
-  stripTypeScriptTypes,
 } = require('internal/modules/helpers');
+const { stripTypeScriptModuleTypes } = require('internal/modules/typescript');
 const packageJsonReader = require('internal/modules/package_json_reader');
 const { getOptionValue, getEmbedderOptions } = require('internal/options');
 const shouldReportRequiredModules = getLazy(() => process.env.WATCH_REPORT_DEPENDENCIES);
@@ -170,7 +170,6 @@ const {
     ERR_REQUIRE_CYCLE_MODULE,
     ERR_REQUIRE_ESM,
     ERR_UNKNOWN_BUILTIN_MODULE,
-    ERR_UNSUPPORTED_NODE_MODULES_TYPE_STRIPPING,
   },
   setArrowMessage,
 } = require('internal/errors');
@@ -1348,10 +1347,7 @@ let emittedRequireModuleWarning = false;
 function loadESMFromCJS(mod, filename) {
   let source = getMaybeCachedSource(mod, filename);
   if (getOptionValue('--experimental-strip-types') && path.extname(filename) === '.mts') {
-    if (isUnderNodeModules(filename)) {
-      throw new ERR_UNSUPPORTED_NODE_MODULES_TYPE_STRIPPING(filename);
-    }
-    source = stripTypeScriptTypes(source, filename);
+    source = stripTypeScriptModuleTypes(source, filename);
   }
   const cascadedLoader = require('internal/modules/esm/loader').getOrInitializeCascadedLoader();
   const isMain = mod[kIsMainSymbol];
@@ -1587,11 +1583,8 @@ function getMaybeCachedSource(mod, filename) {
 }
 
 function loadCTS(module, filename) {
-  if (isUnderNodeModules(filename)) {
-    throw new ERR_UNSUPPORTED_NODE_MODULES_TYPE_STRIPPING(filename);
-  }
   const source = getMaybeCachedSource(module, filename);
-  const code = stripTypeScriptTypes(source, filename);
+  const code = stripTypeScriptModuleTypes(source, filename);
   module._compile(code, filename, 'commonjs');
 }
 
@@ -1601,12 +1594,9 @@ function loadCTS(module, filename) {
  * @param {string} filename The file path of the module
  */
 function loadTS(module, filename) {
-  if (isUnderNodeModules(filename)) {
-    throw new ERR_UNSUPPORTED_NODE_MODULES_TYPE_STRIPPING(filename);
-  }
   // If already analyzed the source, then it will be cached.
   const source = getMaybeCachedSource(module, filename);
-  const content = stripTypeScriptTypes(source, filename);
+  const content = stripTypeScriptModuleTypes(source, filename);
   let format;
   const pkg = packageJsonReader.getNearestParentPackageJSON(filename);
   // Function require shouldn't be used in ES modules.
@@ -1626,7 +1616,7 @@ function loadTS(module, filename) {
     if (Module._cache[parentPath]) {
       let parentSource;
       try {
-        parentSource = stripTypeScriptTypes(fs.readFileSync(parentPath, 'utf8'), parentPath);
+        parentSource = stripTypeScriptModuleTypes(fs.readFileSync(parentPath, 'utf8'), parentPath);
       } catch {
         // Continue regardless of error.
       }

lib/internal/modules/esm/get_format.js

@@ -164,9 +164,10 @@ function getFileProtocolModuleFormat(url, context = { __proto__: null }, ignoreE
         // Since experimental-strip-types depends on detect-module, we always return null
         // if source is undefined.
         if (!source) { return null; }
-        const { stripTypeScriptTypes, stringify } = require('internal/modules/helpers');
+        const { stringify } = require('internal/modules/helpers');
+        const { stripTypeScriptModuleTypes } = require('internal/modules/typescript');
         const stringifiedSource = stringify(source);
-        const parsedSource = stripTypeScriptTypes(stringifiedSource, fileURLToPath(url));
+        const parsedSource = stripTypeScriptModuleTypes(stringifiedSource, fileURLToPath(url));
         const detectedFormat = detectModuleFormat(parsedSource, url);
         const format = `${detectedFormat}-typescript`;
         if (format === 'module-typescript' && foundPackageJson) {

lib/internal/modules/esm/load.js

@@ -4,7 +4,6 @@ const {
   RegExpPrototypeExec,
 } = primordials;
 const {
-  isUnderNodeModules,
   kEmptyObject,
 } = require('internal/util');
 
@@ -23,7 +22,6 @@ const {
   ERR_INVALID_URL,
   ERR_UNKNOWN_MODULE_FORMAT,
   ERR_UNSUPPORTED_ESM_URL_SCHEME,
-  ERR_UNSUPPORTED_NODE_MODULES_TYPE_STRIPPING,
 } = require('internal/errors').codes;
 
 const {
@@ -131,12 +129,6 @@ async function defaultLoad(url, context = kEmptyObject) {
 
   validateAttributes(url, format, importAttributes);
 
-  if (getOptionValue('--experimental-strip-types') &&
-    (format === 'module-typescript' || format === 'commonjs-typescript') &&
-    isUnderNodeModules(url)) {
-    throw new ERR_UNSUPPORTED_NODE_MODULES_TYPE_STRIPPING(url);
-  }
-
   return {
     __proto__: null,
     format,

lib/internal/modules/esm/translators.js

@@ -30,10 +30,10 @@ const {
   assertBufferSource,
   loadBuiltinModule,
   stringify,
-  stripTypeScriptTypes,
   stripBOM,
   urlToFilename,
 } = require('internal/modules/helpers');
+const { stripTypeScriptModuleTypes } = require('internal/modules/typescript');
 const {
   kIsCachedByESMLoader,
   Module: CJSModule,
@@ -244,7 +244,7 @@ translators.set('require-commonjs', (url, source, isMain) => {
 translators.set('require-commonjs-typescript', (url, source, isMain) => {
   emitExperimentalWarning('Type Stripping');
   assert(cjsParse);
-  const code = stripTypeScriptTypes(stringify(source), url);
+  const code = stripTypeScriptModuleTypes(stringify(source), url);
   return createCJSModuleWrap(url, code);
 });
 
@@ -459,7 +459,7 @@ translators.set('wasm', async function(url, source) {
 translators.set('commonjs-typescript', function(url, source) {
   emitExperimentalWarning('Type Stripping');
   assertBufferSource(source, true, 'load');
-  const code = stripTypeScriptTypes(stringify(source), url);
+  const code = stripTypeScriptModuleTypes(stringify(source), url);
   debug(`Translating TypeScript ${url}`);
   return FunctionPrototypeCall(translators.get('commonjs'), this, url, code, false);
 });
@@ -468,7 +468,7 @@ translators.set('commonjs-typescript', function(url, source) {
 translators.set('module-typescript', function(url, source) {
   emitExperimentalWarning('Type Stripping');
   assertBufferSource(source, true, 'load');
-  const code = stripTypeScriptTypes(stringify(source), url);
+  const code = stripTypeScriptModuleTypes(stringify(source), url);
   debug(`Translating TypeScript ${url}`);
   return FunctionPrototypeCall(translators.get('module'), this, url, code, false);
 });