Rename all d.ts files to d.mts in esm output dir

Author: Brijesh Bittu

packages/mui-utils/package.json

@@ -27,9 +27,9 @@
   "scripts": {
     "build": "pnpm build:node && pnpm build:stable && pnpm build:types && pnpm build:copy-files",
     "build:node": "node ../../scripts/build.mjs node",
-    "build:stable": "node ../../scripts/build.mjs stable --verbose",
-    "build:copy-files": "node ../../scripts/copyFiles.mjs",
-    "build:types": "tsx ../../scripts/buildTypes.mts",
+    "build:stable": "MUI_EXPERIMENTAL_MJS=true node ../../scripts/build.mjs stable --verbose",
+    "build:copy-files": "MUI_EXPERIMENTAL_MJS=true node ../../scripts/copyFiles.mjs",
+    "build:types": "MUI_EXPERIMENTAL_MJS=true tsx ../../scripts/buildTypes.mts",
     "prebuild": "rimraf build tsconfig.build.tsbuildinfo",
     "release": "pnpm build && pnpm publish",
     "test": "cd ../../ && cross-env NODE_ENV=test mocha 'packages/mui-utils/**/*.test.?(c|m)[jt]s?(x)'",

scripts/build.mjs

@@ -1,3 +1,4 @@
+/* eslint-disable no-console */
 import childProcess from 'child_process';
 import path from 'path';
 import { promisify } from 'util';
@@ -58,11 +59,10 @@ async function run(argv) {
 
   let outFileExtension = '.js';
 
-  if (EXPERIMENTAL_MJS && (bundle === 'stable')) {
+  if (EXPERIMENTAL_MJS && bundle === 'stable') {
     outFileExtension = '.mjs';
   }
 
-  console.log(EXPERIMENTAL_MJS)
   console.log(`Building ${bundle} bundle with outFileExtension: ${outFileExtension}`);
 
   const relativeOutDir = {

scripts/buildTypes.mts

@@ -8,6 +8,9 @@ import { parse } from 'jsonc-parser';
 
 const $$ = $({ stdio: 'inherit' });
 
+// Use .mjs extension for ESM output files if the MUI_EXPERIMENTAL_MJS environment variable is set.
+const EXPERIMENTAL_MJS = !!process.env.MUI_EXPERIMENTAL_MJS;
+
 async function emitDeclarations(tsconfig: string, outDir: string) {
   // eslint-disable-next-line no-console
   console.log(`Building types for ${path.resolve(tsconfig)}`);
@@ -70,6 +73,22 @@ async function copyDeclarations(sourceDirectory: string, destinationDirectory: s
   });
 }
 
+async function renameDtsFilesToDmts(sourceDirectory: string) {
+  const dtsFiles = await glob('**/*.d.ts', { absolute: true, cwd: sourceDirectory });
+  if (dtsFiles.length === 0) {
+    console.warn('No .d.ts files found in the directory. Skipping renaming to .d.mts');
+    return;
+  }
+
+  console.log('Renaming .d.ts files to .d.mts files in', sourceDirectory);
+  await Promise.all(
+    dtsFiles.map(async (dtsFile) => {
+      const mtsFile = dtsFile.replace(/\.d\.ts$/, '.d.mts');
+      await fs.rename(dtsFile, mtsFile);
+    }),
+  );
+}
+
 interface HandlerArgv {
   skipTsc: boolean;
   cjsDir: string;
@@ -84,10 +103,6 @@ async function main(argv: HandlerArgv) {
     () => false,
   );
 
-  const tsConfig = tsconfigExists
-    ? (parse(await fs.readFile(tsconfigPath, 'utf-8')) as { compilerOptions: { outDir: string } })
-    : null;
-
   const srcPath = path.join(packageRoot, 'src');
   const buildFolder = path.join(packageRoot, 'build');
   const esmDir = path.join(buildFolder, 'esm');
@@ -107,11 +122,15 @@ async function main(argv: HandlerArgv) {
     await emitDeclarations(tsconfigPath, esmDir);
   }
 
-  await copyDeclarations(esmDir, cjsDir)
+  await copyDeclarations(esmDir, cjsDir);
 
   await postProcessImports(esmDir, argv.removeCss);
   await postProcessImports(cjsDir, argv.removeCss);
 
+  if (EXPERIMENTAL_MJS) {
+    await renameDtsFilesToDmts(esmDir);
+  }
+
   const tsbuildinfo = await glob('**/*.tsbuildinfo', { absolute: true, cwd: buildFolder });
   await Promise.all(tsbuildinfo.map(async (file) => fs.rm(file)));
 }

scripts/copyFiles.mjs

@@ -16,17 +16,19 @@ async function addLicense(packageData) {
  */
 `;
   await Promise.all(
-    ['./index.js', './esm/index.js', './modern/index.js', './node/index.js'].map(async (file) => {
-      try {
-        await prepend(path.resolve(buildPath, file), license);
-      } catch (err) {
-        if (err.code === 'ENOENT') {
-          console.log(`Skipped license for ${file}`);
-        } else {
-          throw err;
+    ['./index.js', './esm/index.js', './esm/index.mjs', './modern/index.js', './node/index.js'].map(
+      async (file) => {
+        try {
+          await prepend(path.resolve(buildPath, file), license);
+        } catch (err) {
+          if (err.code === 'ENOENT') {
+            console.log(`Skipped license for ${file}`);
+          } else {
+            throw err;
+          }
         }
-      }
-    }),
+      },
+    ),
   );
 }