diff --git a/.github/generated/ast_changes_watch_list.yml b/.github/generated/ast_changes_watch_list.yml
index d826c8b346af3..5142ad60a18f4 100644
--- a/.github/generated/ast_changes_watch_list.yml
+++ b/.github/generated/ast_changes_watch_list.yml
@@ -3,7 +3,7 @@
 
 src:
   - '.github/generated/ast_changes_watch_list.yml'
-  - 'apps/oxlint/src-js/generated/constants.mjs'
+  - 'apps/oxlint/src-js/generated/constants.js'
   - 'apps/oxlint/src/generated/raw_transfer_constants.rs'
   - 'crates/oxc_allocator/src/generated/assert_layouts.rs'
   - 'crates/oxc_allocator/src/generated/fixed_size_constants.rs'
@@ -66,16 +66,16 @@ src:
   - 'crates/oxc_syntax/src/serialize.rs'
   - 'crates/oxc_syntax/src/symbol.rs'
   - 'crates/oxc_traverse/src/generated/scopes_collector.rs'
-  - 'napi/parser/generated/constants.mjs'
-  - 'napi/parser/generated/deserialize/js.mjs'
-  - 'napi/parser/generated/deserialize/ts.mjs'
-  - 'napi/parser/generated/lazy/constructors.mjs'
-  - 'napi/parser/generated/lazy/types.mjs'
-  - 'napi/parser/generated/lazy/walk.mjs'
-  - 'napi/parser/generated/visit/keys.mjs'
-  - 'napi/parser/generated/visit/types.mjs'
-  - 'napi/parser/generated/visit/visitor.d.mts'
-  - 'napi/parser/generated/visit/walk.mjs'
+  - 'napi/parser/generated/constants.js'
+  - 'napi/parser/generated/deserialize/js.js'
+  - 'napi/parser/generated/deserialize/ts.js'
+  - 'napi/parser/generated/lazy/constructors.js'
+  - 'napi/parser/generated/lazy/types.js'
+  - 'napi/parser/generated/lazy/walk.js'
+  - 'napi/parser/generated/visit/keys.js'
+  - 'napi/parser/generated/visit/types.js'
+  - 'napi/parser/generated/visit/visitor.d.ts'
+  - 'napi/parser/generated/visit/walk.js'
   - 'napi/parser/src/generated/assert_layouts.rs'
   - 'napi/parser/src/generated/derive_estree.rs'
   - 'napi/parser/src/generated/raw_transfer_constants.rs'
diff --git a/.github/workflows/release_oxlint.yml b/.github/workflows/release_oxlint.yml
index 5e23b1a503f60..bfdcb028c82f2 100644
--- a/.github/workflows/release_oxlint.yml
+++ b/.github/workflows/release_oxlint.yml
@@ -212,7 +212,7 @@ jobs:
 
       - name: Generate npm packages
         run: |
-          node npm/oxlint/scripts/generate-packages.mjs
+          node npm/oxlint/scripts/generate-packages.js
           cat npm/oxlint/package.json
           for package in npm/oxlint*; do cat $package/package.json ; echo ; done
 
diff --git a/apps/oxlint/package.json b/apps/oxlint/package.json
index 56a5160f15ab6..d78d1eb3f9d44 100644
--- a/apps/oxlint/package.json
+++ b/apps/oxlint/package.json
@@ -1,9 +1,9 @@
 {
   "name": "oxlint",
   "version": "1.16.0",
+  "type": "module",
   "main": "dist/index.js",
   "bin": "dist/cli.js",
-  "type": "module",
   "scripts": {
     "build": "pnpm run build-napi-release && pnpm run build-js",
     "build-dev": "pnpm run build-napi && pnpm run build-js",
diff --git a/apps/oxlint/scripts/build.js b/apps/oxlint/scripts/build.js
index c813a1b092e84..ead8553f002e9 100755
--- a/apps/oxlint/scripts/build.js
+++ b/apps/oxlint/scripts/build.js
@@ -26,16 +26,16 @@ console.log('Copying files from parser...');
 const parserFilePaths = [
   // Lazy implementation
   /*
-  'src-js/raw-transfer/lazy-common.mjs',
-  'src-js/raw-transfer/node-array.mjs',
-  'generated/lazy/constructors.mjs',
-  'generated/lazy/types.mjs',
-  'generated/lazy/walk.mjs',
+  'src-js/raw-transfer/lazy-common.js',
+  'src-js/raw-transfer/node-array.js',
+  'generated/lazy/constructors.js',
+  'generated/lazy/types.js',
+  'generated/lazy/walk.js',
   */
-  'generated/deserialize/ts.mjs',
-  'generated/visit/types.mjs',
-  'generated/visit/visitor.d.mts',
-  'generated/visit/walk.mjs',
+  'generated/deserialize/ts.js',
+  'generated/visit/types.js',
+  'generated/visit/visitor.d.ts',
+  'generated/visit/walk.js',
 ];
 
 for (const parserFilePath of parserFilePaths) {
diff --git a/apps/oxlint/src-js/generated/constants.mjs b/apps/oxlint/src-js/generated/constants.js
similarity index 100%
rename from apps/oxlint/src-js/generated/constants.mjs
rename to apps/oxlint/src-js/generated/constants.js
diff --git a/apps/oxlint/src-js/plugins/lint.ts b/apps/oxlint/src-js/plugins/lint.ts
index 2f9a08541a958..1487669daebc3 100644
--- a/apps/oxlint/src-js/plugins/lint.ts
+++ b/apps/oxlint/src-js/plugins/lint.ts
@@ -3,7 +3,7 @@ import {
   SOURCE_LEN_OFFSET,
   // TODO(camc314): we need to generate `.d.ts` file for this module.
   // @ts-expect-error
-} from '../generated/constants.mjs';
+} from '../generated/constants.js';
 import { diagnostics, setupContextForFile } from './context.js';
 import { registeredRules } from './load.js';
 import { assertIs } from './utils.js';
@@ -12,15 +12,15 @@ import { addVisitorToCompiled, compiledVisitor, finalizeCompiledVisitor, initCom
 // Lazy implementation
 /*
 // @ts-expect-error we need to generate `.d.ts` file for this module.
-import { TOKEN } from '../../dist/src-js/raw-transfer/lazy-common.mjs';
+import { TOKEN } from '../../dist/src-js/raw-transfer/lazy-common.js';
 // @ts-expect-error we need to generate `.d.ts` file for this module.
-import { walkProgram } from '../../dist/generated/lazy/walk.mjs';
+import { walkProgram } from '../../dist/generated/lazy/walk.js';
 */
 
 // @ts-expect-error we need to generate `.d.ts` file for this module
-import { deserializeProgramOnly } from '../../dist/generated/deserialize/ts.mjs';
+import { deserializeProgramOnly } from '../../dist/generated/deserialize/ts.js';
 // @ts-expect-error we need to generate `.d.ts` file for this module
-import { walkProgram } from '../../dist/generated/visit/walk.mjs';
+import { walkProgram } from '../../dist/generated/visit/walk.js';
 
 import type { AfterHook } from './types.ts';
 
diff --git a/apps/oxlint/src-js/plugins/types.ts b/apps/oxlint/src-js/plugins/types.ts
index 9ee44985eaccc..d9e34df585579 100644
--- a/apps/oxlint/src-js/plugins/types.ts
+++ b/apps/oxlint/src-js/plugins/types.ts
@@ -6,7 +6,7 @@ export interface Visitor {
 }
 */
 
-import type { VisitorObject as Visitor } from '../../dist/generated/visit/visitor.d.mts';
+import type { VisitorObject as Visitor } from '../../dist/generated/visit/visitor.d.ts';
 export type { Visitor };
 
 // Hook function that runs before traversal.
diff --git a/apps/oxlint/src-js/plugins/visitor.ts b/apps/oxlint/src-js/plugins/visitor.ts
index 3b83ed4bafca8..a5c30d2a691b1 100644
--- a/apps/oxlint/src-js/plugins/visitor.ts
+++ b/apps/oxlint/src-js/plugins/visitor.ts
@@ -75,12 +75,12 @@
 // Lazy implementation
 /*
 // TODO(camc314): we need to generate `.d.ts` file for this module.
-import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../dist/generated/lazy/types.mjs';
+import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../dist/generated/lazy/types.js';
 */
 
 // TODO(camc314): we need to generate `.d.ts` file for this module.
 // @ts-expect-error
-import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../dist/generated/visit/types.mjs';
+import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../dist/generated/visit/types.js';
 import { assertIs } from './utils.js';
 
 import type { CompiledVisitorEntry, EnterExit, Node, VisitFn, Visitor } from './types.ts';
diff --git a/apps/oxlint/test/compile-visitor.test.ts b/apps/oxlint/test/compile-visitor.test.ts
index 4e20a73532a71..719e723be8e81 100644
--- a/apps/oxlint/test/compile-visitor.test.ts
+++ b/apps/oxlint/test/compile-visitor.test.ts
@@ -3,11 +3,11 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 /*
 // TODO(camc314): we need to generate `.d.ts` file for this module.
 // @ts-expect-error
-import { NODE_TYPE_IDS_MAP } from '../dist/generated/lazy/types.mjs';
+import { NODE_TYPE_IDS_MAP } from '../dist/generated/lazy/types.js';
 */
 // TODO(camc314): we need to generate `.d.ts` file for this module
 // @ts-expect-error
-import { NODE_TYPE_IDS_MAP } from '../dist/generated/visit/types.mjs';
+import { NODE_TYPE_IDS_MAP } from '../dist/generated/visit/types.js';
 import {
   addVisitorToCompiled,
   compiledVisitor,
diff --git a/apps/oxlint/vitest.config.mts b/apps/oxlint/vitest.config.ts
similarity index 100%
rename from apps/oxlint/vitest.config.mts
rename to apps/oxlint/vitest.config.ts
diff --git a/dprint.json b/dprint.json
index 0726e30017aba..00e18b0af0f7c 100644
--- a/dprint.json
+++ b/dprint.json
@@ -27,8 +27,7 @@
     "napi/{parser,transform,minify,playground}/**/wasi-worker-browser.mjs",
     "napi/{parser,transform,minify,playground}/**/wasi-worker.mjs",
     "napi/{parser,transform,minify,playground}/**/browser.js",
-    "napi/parser/src-js/bindings.mjs",
-    "napi/parser/src-js/index.d.mts",
+    "napi/parser/src-js/bindings.js",
     "npm/*/package.json",
     "npm/oxlint/configuration_schema.json",
     "npm/oxc-wasm/**",
diff --git a/napi/parser/bench.bench.mjs b/napi/parser/bench.bench.js
similarity index 95%
rename from napi/parser/bench.bench.mjs
rename to napi/parser/bench.bench.js
index 6ec10754204a1..42a58553b0b1e 100644
--- a/napi/parser/bench.bench.mjs
+++ b/napi/parser/bench.bench.js
@@ -1,17 +1,17 @@
 import { writeFile } from 'node:fs/promises';
 import { join as pathJoin } from 'node:path';
 import { bench, describe } from 'vitest';
-import { parseSyncRaw } from './src-js/bindings.mjs';
-import { parseAsync, parseSync } from './src-js/index.mjs';
+import { parseSyncRaw } from './src-js/bindings.js';
+import { parseAsync, parseSync } from './src-js/index.js';
 
 // Internals
-import { DATA_POINTER_POS_32, PROGRAM_OFFSET } from './generated/constants.mjs';
-import { deserialize as deserializeJS } from './generated/deserialize/js.mjs';
-import { deserialize as deserializeTS } from './generated/deserialize/ts.mjs';
-import { walkProgram } from './generated/lazy/walk.mjs';
-import { isJsAst, prepareRaw, returnBufferToCache } from './src-js/raw-transfer/common.mjs';
-import { TOKEN } from './src-js/raw-transfer/lazy-common.mjs';
-import { getVisitorsArr, Visitor } from './src-js/raw-transfer/visitor.mjs';
+import { DATA_POINTER_POS_32, PROGRAM_OFFSET } from './generated/constants.js';
+import { deserialize as deserializeJS } from './generated/deserialize/js.js';
+import { deserialize as deserializeTS } from './generated/deserialize/ts.js';
+import { walkProgram } from './generated/lazy/walk.js';
+import { isJsAst, prepareRaw, returnBufferToCache } from './src-js/raw-transfer/common.js';
+import { TOKEN } from './src-js/raw-transfer/lazy-common.js';
+import { getVisitorsArr, Visitor } from './src-js/raw-transfer/visitor.js';
 
 // Same fixtures as used in Rust parser benchmarks
 let fixtureUrls = [
diff --git a/napi/parser/example.mjs b/napi/parser/example.js
similarity index 87%
rename from napi/parser/example.mjs
rename to napi/parser/example.js
index 5330eeff5b382..a832738e715a2 100644
--- a/napi/parser/example.mjs
+++ b/napi/parser/example.js
@@ -1,10 +1,10 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { parseArgs } from 'node:util';
-import { parseSync } from './src-js/index.mjs';
+import { parseSync } from './src-js/index.js';
 
 // usage:
-// node napi/parser/example.mjs test.ts
+// node napi/parser/example.js test.ts
 
 process.chdir(path.join(import.meta.dirname, '../..'));
 
diff --git a/napi/parser/generated/constants.mjs b/napi/parser/generated/constants.js
similarity index 100%
rename from napi/parser/generated/constants.mjs
rename to napi/parser/generated/constants.js
diff --git a/napi/parser/generated/deserialize/js.mjs b/napi/parser/generated/deserialize/js.js
similarity index 100%
rename from napi/parser/generated/deserialize/js.mjs
rename to napi/parser/generated/deserialize/js.js
diff --git a/napi/parser/generated/deserialize/ts.mjs b/napi/parser/generated/deserialize/ts.js
similarity index 100%
rename from napi/parser/generated/deserialize/ts.mjs
rename to napi/parser/generated/deserialize/ts.js
diff --git a/napi/parser/generated/lazy/constructors.mjs b/napi/parser/generated/lazy/constructors.js
similarity index 99%
rename from napi/parser/generated/lazy/constructors.mjs
rename to napi/parser/generated/lazy/constructors.js
index 2bb0a06e724c9..ceeae7b3a6828 100644
--- a/napi/parser/generated/lazy/constructors.mjs
+++ b/napi/parser/generated/lazy/constructors.js
@@ -1,8 +1,8 @@
 // Auto-generated code, DO NOT EDIT DIRECTLY!
 // To edit this generated file you have to edit `tasks/ast_tools/src/generators/raw_transfer_lazy.rs`.
 
-import { constructorError, TOKEN } from '../../src-js/raw-transfer/lazy-common.mjs';
-import { NodeArray } from '../../src-js/raw-transfer/node-array.mjs';
+import { constructorError, TOKEN } from '../../src-js/raw-transfer/lazy-common.js';
+import { NodeArray } from '../../src-js/raw-transfer/node-array.js';
 
 const textDecoder = new TextDecoder('utf-8', { ignoreBOM: true }),
   decodeStr = textDecoder.decode.bind(textDecoder),
diff --git a/napi/parser/generated/lazy/types.mjs b/napi/parser/generated/lazy/types.js
similarity index 100%
rename from napi/parser/generated/lazy/types.mjs
rename to napi/parser/generated/lazy/types.js
diff --git a/napi/parser/generated/lazy/walk.mjs b/napi/parser/generated/lazy/walk.js
similarity index 99%
rename from napi/parser/generated/lazy/walk.mjs
rename to napi/parser/generated/lazy/walk.js
index 8832eeafddd5b..a430af2c389c4 100644
--- a/napi/parser/generated/lazy/walk.mjs
+++ b/napi/parser/generated/lazy/walk.js
@@ -181,7 +181,7 @@ import {
   WhileStatement,
   WithStatement,
   YieldExpression,
-} from './constructors.mjs';
+} from './constructors.js';
 
 export { walkProgram };
 
diff --git a/napi/parser/generated/visit/keys.mjs b/napi/parser/generated/visit/keys.js
similarity index 100%
rename from napi/parser/generated/visit/keys.mjs
rename to napi/parser/generated/visit/keys.js
diff --git a/napi/parser/generated/visit/types.mjs b/napi/parser/generated/visit/types.js
similarity index 100%
rename from napi/parser/generated/visit/types.mjs
rename to napi/parser/generated/visit/types.js
diff --git a/napi/parser/generated/visit/visitor.d.mts b/napi/parser/generated/visit/visitor.d.ts
similarity index 100%
rename from napi/parser/generated/visit/visitor.d.mts
rename to napi/parser/generated/visit/visitor.d.ts
diff --git a/napi/parser/generated/visit/walk.mjs b/napi/parser/generated/visit/walk.js
similarity index 100%
rename from napi/parser/generated/visit/walk.mjs
rename to napi/parser/generated/visit/walk.js
diff --git a/napi/parser/package.json b/napi/parser/package.json
index f9d63eb4f05dd..d4eedf84435a5 100644
--- a/napi/parser/package.json
+++ b/napi/parser/package.json
@@ -2,20 +2,20 @@
   "name": "oxc-parser",
   "version": "0.91.0",
   "type": "module",
-  "main": "src-js/index.mjs",
-  "browser": "src-js/wasm.mjs",
+  "main": "src-js/index.js",
+  "browser": "src-js/wasm.js",
   "scripts": {
-    "build-dev": "napi build --esm --platform --js bindings.mjs --dts index.d.mts --output-dir src-js",
+    "build-dev": "napi build --esm --platform --js bindings.js --dts index.d.ts --output-dir src-js",
     "build-test": "pnpm run build-dev --profile coverage",
     "build": "pnpm run build-dev --features allocator --release",
-    "postbuild-dev": "node scripts/patch.mjs",
+    "postbuild-dev": "node scripts/patch.js",
     "build-wasi": "pnpm run build-dev --release --target wasm32-wasip1-threads",
     "build-npm-dir": "rm -rf npm-dir && napi create-npm-dirs --npm-dir npm-dir && pnpm napi artifacts --npm-dir npm-dir --output-dir src-js",
-    "build-browser-bundle": "node scripts/build-browser-bundle.mjs",
+    "build-browser-bundle": "node scripts/build-browser-bundle.js",
     "test": "tsc && pnpm run test-node run",
     "test-node": "vitest --dir ./test",
-    "test-browser": "vitest -c vitest.config.browser.mts",
-    "bench": "vitest bench --run ./bench.bench.mjs"
+    "test-browser": "vitest -c vitest.config.browser.ts",
+    "bench": "vitest bench --run ./bench.bench.js"
   },
   "engines": {
     "node": "^20.19.0 || >=22.12.0"
@@ -38,31 +38,31 @@
     "url": "https://github.com/sponsors/Boshen"
   },
   "files": [
-    "generated/constants.mjs",
-    "generated/deserialize/js.mjs",
-    "generated/deserialize/ts.mjs",
-    "generated/lazy/constructors.mjs",
-    "generated/lazy/types.mjs",
-    "generated/lazy/walk.mjs",
-    "generated/visit/keys.mjs",
-    "generated/visit/types.mjs",
-    "generated/visit/visitor.d.mts",
-    "generated/visit/walk.mjs",
-    "src-js/bindings.mjs",
-    "src-js/index.d.mts",
-    "src-js/index.mjs",
-    "src-js/wasm.mjs",
+    "generated/constants.js",
+    "generated/deserialize/js.js",
+    "generated/deserialize/ts.js",
+    "generated/lazy/constructors.js",
+    "generated/lazy/types.js",
+    "generated/lazy/walk.js",
+    "generated/visit/keys.js",
+    "generated/visit/types.js",
+    "generated/visit/visitor.d.ts",
+    "generated/visit/walk.js",
+    "src-js/bindings.js",
+    "src-js/index.d.ts",
+    "src-js/index.js",
+    "src-js/wasm.js",
     "src-js/webcontainer-fallback.cjs",
-    "src-js/wrap.mjs",
-    "src-js/raw-transfer/common.mjs",
-    "src-js/raw-transfer/eager.mjs",
-    "src-js/raw-transfer/lazy.mjs",
-    "src-js/raw-transfer/lazy-common.mjs",
-    "src-js/raw-transfer/node-array.mjs",
-    "src-js/raw-transfer/supported.mjs",
-    "src-js/raw-transfer/visitor.mjs",
-    "src-js/visit/index.mjs",
-    "src-js/visit/visitor.mjs"
+    "src-js/wrap.js",
+    "src-js/raw-transfer/common.js",
+    "src-js/raw-transfer/eager.js",
+    "src-js/raw-transfer/lazy.js",
+    "src-js/raw-transfer/lazy-common.js",
+    "src-js/raw-transfer/node-array.js",
+    "src-js/raw-transfer/supported.js",
+    "src-js/raw-transfer/visitor.js",
+    "src-js/visit/index.js",
+    "src-js/visit/visitor.js"
   ],
   "publishConfig": {
     "registry": "https://registry.npmjs.org/",
@@ -107,6 +107,6 @@
         "fs": false
       }
     },
-    "dtsHeaderFile": "src-js/header.d.mts"
+    "dtsHeaderFile": "src-js/header.d.ts"
   }
 }
diff --git a/napi/parser/scripts/build-browser-bundle.mjs b/napi/parser/scripts/build-browser-bundle.js
similarity index 79%
rename from napi/parser/scripts/build-browser-bundle.mjs
rename to napi/parser/scripts/build-browser-bundle.js
index ec161a68e58c9..bccf90a3bd80e 100644
--- a/napi/parser/scripts/build-browser-bundle.mjs
+++ b/napi/parser/scripts/build-browser-bundle.js
@@ -13,10 +13,10 @@ async function main() {
     },
   });
 
-  // bundle wasm.mjs -> browser-bundle.mjs
+  // bundle wasm.js -> browser-bundle.js
   await esbuild.build({
-    entryPoints: ['./src-js/wasm.mjs'],
-    outfile: 'browser-bundle.mjs',
+    entryPoints: ['./src-js/wasm.js'],
+    outfile: 'browser-bundle.js',
     alias: {
       '@oxc-parser/binding-wasm32-wasi': './src-js/parser.wasi-browser.js',
     },
@@ -48,14 +48,14 @@ async function main() {
   if (args.values.npmDir) {
     const pkgDir = path.resolve(args.values.npmDir, 'wasm32-wasi');
 
-    // add `browser-bundle.mjs` to `package.json:files`
+    // add `browser-bundle.js` to `package.json:files`
     const pkgFile = path.join(pkgDir, 'package.json');
     const pkg = JSON.parse(fs.readFileSync(pkgFile, 'utf8'));
-    pkg.files.push('browser-bundle.mjs');
+    pkg.files.push('browser-bundle.js');
     fs.writeFileSync(pkgFile, JSON.stringify(pkg, null, 2));
 
-    // copy `browser-bundle.mjs` to `<npmDir>/wasm32-wasi`
-    fs.cpSync('browser-bundle.mjs', path.join(pkgDir, 'browser-bundle.mjs'));
+    // copy `browser-bundle.js` to `<npmDir>/wasm32-wasi`
+    fs.cpSync('browser-bundle.js', path.join(pkgDir, 'browser-bundle.js'));
   }
 }
 
diff --git a/napi/parser/scripts/patch.mjs b/napi/parser/scripts/patch.js
similarity index 92%
rename from napi/parser/scripts/patch.mjs
rename to napi/parser/scripts/patch.js
index 35fe1cffe5207..79ce4a2b3acea 100644
--- a/napi/parser/scripts/patch.mjs
+++ b/napi/parser/scripts/patch.js
@@ -1,6 +1,6 @@
 import fs from 'node:fs';
 
-const filename = './src-js/bindings.mjs';
+const filename = './src-js/bindings.js';
 let data = fs.readFileSync(filename, 'utf-8');
 
 data = data.replace(
diff --git a/napi/parser/scripts/visitor-keys.mjs b/napi/parser/scripts/visitor-keys.js
similarity index 100%
rename from napi/parser/scripts/visitor-keys.mjs
rename to napi/parser/scripts/visitor-keys.js
diff --git a/napi/parser/src-js/bindings.mjs b/napi/parser/src-js/bindings.js
similarity index 100%
rename from napi/parser/src-js/bindings.mjs
rename to napi/parser/src-js/bindings.js
diff --git a/napi/parser/src-js/header.d.mts b/napi/parser/src-js/header.d.ts
similarity index 98%
rename from napi/parser/src-js/header.d.mts
rename to napi/parser/src-js/header.d.ts
index 542727d2a3cbb..214504e9d6885 100644
--- a/napi/parser/src-js/header.d.mts
+++ b/napi/parser/src-js/header.d.ts
@@ -2,7 +2,7 @@
 /* eslint-disable */
 
 import type { Program } from '@oxc-project/types';
-import type { VisitorObject } from '../generated/visit/visitor.d.mts';
+import type { VisitorObject } from '../generated/visit/visitor.d.ts';
 
 export * from '@oxc-project/types';
 
diff --git a/napi/parser/src-js/index.d.mts b/napi/parser/src-js/index.d.ts
similarity index 99%
rename from napi/parser/src-js/index.d.mts
rename to napi/parser/src-js/index.d.ts
index 9ef6ee174f22b..610409bc887fd 100644
--- a/napi/parser/src-js/index.d.mts
+++ b/napi/parser/src-js/index.d.ts
@@ -2,7 +2,7 @@
 /* eslint-disable */
 
 import type { Program } from '@oxc-project/types';
-import type { VisitorObject } from '../generated/visit/visitor.d.mts';
+import type { VisitorObject } from '../generated/visit/visitor.d.ts';
 
 export * from '@oxc-project/types';
 
diff --git a/napi/parser/src-js/index.mjs b/napi/parser/src-js/index.js
similarity index 93%
rename from napi/parser/src-js/index.mjs
rename to napi/parser/src-js/index.js
index f289f65ef5620..ed1a6385aef8d 100644
--- a/napi/parser/src-js/index.mjs
+++ b/napi/parser/src-js/index.js
@@ -1,9 +1,9 @@
 import { createRequire } from 'node:module';
-import { parseAsync as parseAsyncBinding, parseSync as parseSyncBinding } from './bindings.mjs';
-import { wrap } from './wrap.mjs';
+import { parseAsync as parseAsyncBinding, parseSync as parseSyncBinding } from './bindings.js';
+import { wrap } from './wrap.js';
 
-export { default as visitorKeys } from '../generated/visit/keys.mjs';
-export { Visitor } from './visit/index.mjs';
+export { default as visitorKeys } from '../generated/visit/keys.js';
+export { Visitor } from './visit/index.js';
 
 export {
   ExportExportNameKind,
@@ -12,8 +12,8 @@ export {
   ImportNameKind,
   ParseResult,
   Severity,
-} from './bindings.mjs';
-export { rawTransferSupported } from './raw-transfer/supported.mjs';
+} from './bindings.js';
+export { rawTransferSupported } from './raw-transfer/supported.js';
 
 const require = createRequire(import.meta.url);
 
@@ -30,7 +30,7 @@ let parseSyncRaw = null,
  */
 function loadRawTransfer() {
   if (parseSyncRaw === null) {
-    ({ parseSyncRaw, parseAsyncRaw } = require('./raw-transfer/eager.mjs'));
+    ({ parseSyncRaw, parseAsyncRaw } = require('./raw-transfer/eager.js'));
   }
 }
 
@@ -40,7 +40,7 @@ function loadRawTransfer() {
  */
 function loadRawTransferLazy() {
   if (parseSyncLazy === null) {
-    ({ parseSyncLazy, parseAsyncLazy, Visitor: LazyVisitor } = require('./raw-transfer/lazy.mjs'));
+    ({ parseSyncLazy, parseAsyncLazy, Visitor: LazyVisitor } = require('./raw-transfer/lazy.js'));
   }
 }
 
diff --git a/napi/parser/src-js/raw-transfer/common.mjs b/napi/parser/src-js/raw-transfer/common.js
similarity index 99%
rename from napi/parser/src-js/raw-transfer/common.mjs
rename to napi/parser/src-js/raw-transfer/common.js
index 0bb3856815e32..72b8192c121ca 100644
--- a/napi/parser/src-js/raw-transfer/common.mjs
+++ b/napi/parser/src-js/raw-transfer/common.js
@@ -1,11 +1,11 @@
 import os from 'node:os';
-import { BUFFER_ALIGN, BUFFER_SIZE, IS_TS_FLAG_POS } from '../../generated/constants.mjs';
+import { BUFFER_ALIGN, BUFFER_SIZE, IS_TS_FLAG_POS } from '../../generated/constants.js';
 import {
   getBufferOffset,
   parseAsyncRaw as parseAsyncRawBinding,
   parseSyncRaw as parseSyncRawBinding,
-} from '../bindings.mjs';
-import { rawTransferSupported } from './supported.mjs';
+} from '../bindings.js';
+import { rawTransferSupported } from './supported.js';
 
 // Throw an error if running on a platform which raw transfer doesn't support.
 //
diff --git a/napi/parser/src-js/raw-transfer/eager.mjs b/napi/parser/src-js/raw-transfer/eager.js
similarity index 97%
rename from napi/parser/src-js/raw-transfer/eager.mjs
rename to napi/parser/src-js/raw-transfer/eager.js
index 37746c3b4a3f1..e12f813223a64 100644
--- a/napi/parser/src-js/raw-transfer/eager.mjs
+++ b/napi/parser/src-js/raw-transfer/eager.js
@@ -1,5 +1,5 @@
 import { createRequire } from 'node:module';
-import { isJsAst, parseAsyncRawImpl, parseSyncRawImpl, returnBufferToCache } from './common.mjs';
+import { isJsAst, parseAsyncRawImpl, parseSyncRawImpl, returnBufferToCache } from './common.js';
 
 const require = createRequire(import.meta.url);
 
@@ -55,7 +55,7 @@ function deserialize(buffer, sourceText, sourceByteLen) {
   // Lazy load deserializer, and deserialize buffer to JS objects
   let data;
   if (isJsAst(buffer)) {
-    if (deserializeJS === null) deserializeJS = require('../../generated/deserialize/js.mjs').deserialize;
+    if (deserializeJS === null) deserializeJS = require('../../generated/deserialize/js.js').deserialize;
 
     // `preserveParens` argument is unconditionally `true` here. If `options` contains `preserveParens: false`,
     // `ParenthesizedExpression` nodes won't be in AST anyway, so the value is irrelevant.
@@ -67,7 +67,7 @@ function deserialize(buffer, sourceText, sourceByteLen) {
       data.comments.unshift({ type: 'Line', value: hashbang.value, start: hashbang.start, end: hashbang.end });
     }
   } else {
-    if (deserializeTS === null) deserializeTS = require('../../generated/deserialize/ts.mjs').deserialize;
+    if (deserializeTS === null) deserializeTS = require('../../generated/deserialize/ts.js').deserialize;
 
     // `preserveParens` argument is unconditionally `true` here. If `options` contains `preserveParens: false`,
     // `ParenthesizedExpression` nodes won't be in AST anyway, so the value is irrelevant.
diff --git a/napi/parser/src-js/raw-transfer/lazy-common.mjs b/napi/parser/src-js/raw-transfer/lazy-common.js
similarity index 100%
rename from napi/parser/src-js/raw-transfer/lazy-common.mjs
rename to napi/parser/src-js/raw-transfer/lazy-common.js
diff --git a/napi/parser/src-js/raw-transfer/lazy.mjs b/napi/parser/src-js/raw-transfer/lazy.js
similarity index 96%
rename from napi/parser/src-js/raw-transfer/lazy.mjs
rename to napi/parser/src-js/raw-transfer/lazy.js
index 9c10ae1d06677..d14dc899f5dc9 100644
--- a/napi/parser/src-js/raw-transfer/lazy.mjs
+++ b/napi/parser/src-js/raw-transfer/lazy.js
@@ -1,10 +1,10 @@
-import { DATA_POINTER_POS_32, PROGRAM_OFFSET } from '../../generated/constants.mjs';
-import { RawTransferData } from '../../generated/lazy/constructors.mjs';
-import { walkProgram } from '../../generated/lazy/walk.mjs';
-import { parseAsyncRawImpl, parseSyncRawImpl, returnBufferToCache } from './common.mjs';
-import { TOKEN } from './lazy-common.mjs';
-import { getVisitorsArr } from './visitor.mjs';
-export { Visitor } from './visitor.mjs';
+import { DATA_POINTER_POS_32, PROGRAM_OFFSET } from '../../generated/constants.js';
+import { RawTransferData } from '../../generated/lazy/constructors.js';
+import { walkProgram } from '../../generated/lazy/walk.js';
+import { parseAsyncRawImpl, parseSyncRawImpl, returnBufferToCache } from './common.js';
+import { TOKEN } from './lazy-common.js';
+import { getVisitorsArr } from './visitor.js';
+export { Visitor } from './visitor.js';
 
 /**
  * Parse JS/TS source synchronously on current thread.
diff --git a/napi/parser/src-js/raw-transfer/node-array.mjs b/napi/parser/src-js/raw-transfer/node-array.js
similarity index 99%
rename from napi/parser/src-js/raw-transfer/node-array.mjs
rename to napi/parser/src-js/raw-transfer/node-array.js
index ee3b42bbe5bce..99dd83d30d2ee 100644
--- a/napi/parser/src-js/raw-transfer/node-array.mjs
+++ b/napi/parser/src-js/raw-transfer/node-array.js
@@ -1,4 +1,4 @@
-import { constructorError, TOKEN } from './lazy-common.mjs';
+import { constructorError, TOKEN } from './lazy-common.js';
 
 // Internal symbol to get `NodeArray` from a proxy wrapping a `NodeArray`.
 //
diff --git a/napi/parser/src-js/raw-transfer/supported.mjs b/napi/parser/src-js/raw-transfer/supported.js
similarity index 98%
rename from napi/parser/src-js/raw-transfer/supported.mjs
rename to napi/parser/src-js/raw-transfer/supported.js
index b3c4c83197d82..d7c45093f6b0d 100644
--- a/napi/parser/src-js/raw-transfer/supported.mjs
+++ b/napi/parser/src-js/raw-transfer/supported.js
@@ -1,4 +1,4 @@
-import { rawTransferSupported as rawTransferSupportedBinding } from '../bindings.mjs';
+import { rawTransferSupported as rawTransferSupportedBinding } from '../bindings.js';
 
 let rawTransferIsSupported = null;
 
diff --git a/napi/parser/src-js/raw-transfer/visitor.mjs b/napi/parser/src-js/raw-transfer/visitor.js
similarity index 98%
rename from napi/parser/src-js/raw-transfer/visitor.mjs
rename to napi/parser/src-js/raw-transfer/visitor.js
index d5e2f1c899384..822b0a1fd0692 100644
--- a/napi/parser/src-js/raw-transfer/visitor.mjs
+++ b/napi/parser/src-js/raw-transfer/visitor.js
@@ -1,4 +1,4 @@
-import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../generated/lazy/types.mjs';
+import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../generated/lazy/types.js';
 
 // Getter for private `#visitorsArr` property of `Visitor` class. Initialized in class body below.
 let getVisitorsArrTemp;
diff --git a/napi/parser/src-js/visit/index.mjs b/napi/parser/src-js/visit/index.js
similarity index 88%
rename from napi/parser/src-js/visit/index.mjs
rename to napi/parser/src-js/visit/index.js
index 4468184657870..060db6483c7ca 100644
--- a/napi/parser/src-js/visit/index.mjs
+++ b/napi/parser/src-js/visit/index.js
@@ -12,8 +12,8 @@ export class Visitor {
   constructor(visitor) {
     if (walkProgram === null) {
       const require = createRequire(import.meta.url);
-      ({ walkProgram } = require('../../generated/visit/walk.mjs'));
-      ({ addVisitorToCompiled, createCompiledVisitor, finalizeCompiledVisitor } = require('./visitor.mjs'));
+      ({ walkProgram } = require('../../generated/visit/walk.js'));
+      ({ addVisitorToCompiled, createCompiledVisitor, finalizeCompiledVisitor } = require('./visitor.js'));
     }
 
     const compiledVisitor = createCompiledVisitor();
diff --git a/napi/parser/src-js/visit/visitor.mjs b/napi/parser/src-js/visit/visitor.js
similarity index 99%
rename from napi/parser/src-js/visit/visitor.mjs
rename to napi/parser/src-js/visit/visitor.js
index cb2ed2ddbea50..8c35c7847bf40 100644
--- a/napi/parser/src-js/visit/visitor.mjs
+++ b/napi/parser/src-js/visit/visitor.js
@@ -74,7 +74,7 @@
 
 // TODO(camc314): we need to generate `.d.ts` file for this module.
 // @ts-expect-error
-import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../generated/visit/types.mjs';
+import { LEAF_NODE_TYPES_COUNT, NODE_TYPE_IDS_MAP, NODE_TYPES_COUNT } from '../../generated/visit/types.js';
 
 const { isArray } = Array;
 
diff --git a/napi/parser/src-js/wasm.mjs b/napi/parser/src-js/wasm.js
similarity index 90%
rename from napi/parser/src-js/wasm.mjs
rename to napi/parser/src-js/wasm.js
index 57dda29f6d55c..a6d3df67e2ea4 100644
--- a/napi/parser/src-js/wasm.mjs
+++ b/napi/parser/src-js/wasm.js
@@ -1,6 +1,6 @@
 export * from '@oxc-parser/binding-wasm32-wasi';
 import * as bindings from '@oxc-parser/binding-wasm32-wasi';
-import { wrap } from './wrap.mjs';
+import { wrap } from './wrap.js';
 
 export async function parseAsync(...args) {
   return wrap(await bindings.parseAsync(...args));
diff --git a/napi/parser/src-js/wrap.mjs b/napi/parser/src-js/wrap.js
similarity index 100%
rename from napi/parser/src-js/wrap.mjs
rename to napi/parser/src-js/wrap.js
diff --git a/napi/parser/test-browser/parse.test.ts b/napi/parser/test-browser/parse.test.ts
index 29b9386b701d5..e42facab2397f 100644
--- a/napi/parser/test-browser/parse.test.ts
+++ b/napi/parser/test-browser/parse.test.ts
@@ -1,5 +1,5 @@
 import { expect, test } from 'vitest';
-import { parseAsync, parseSync } from '../src-js/wasm.mjs';
+import { parseAsync, parseSync } from '../src-js/wasm.js';
 
 test('parseSync', () => {
   const result = parseSync('test.js', 'ok');
diff --git a/napi/parser/test/esm.test.ts b/napi/parser/test/esm.test.ts
index 7b6b137f3d538..fc893ff5ed16a 100644
--- a/napi/parser/test/esm.test.ts
+++ b/napi/parser/test/esm.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, test } from 'vitest';
 
-import { parseSync } from '../src-js/index.mjs';
+import { parseSync } from '../src-js/index.js';
 
 describe('esm', () => {
   // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#syntax
diff --git a/napi/parser/test/lazy-deserialization.test.ts b/napi/parser/test/lazy-deserialization.test.ts
index f3fb03d52bbd2..b004edde07f2a 100644
--- a/napi/parser/test/lazy-deserialization.test.ts
+++ b/napi/parser/test/lazy-deserialization.test.ts
@@ -4,7 +4,7 @@
 
 import { describe, expect, it } from 'vitest';
 
-import { parseSync } from '../src-js/index.mjs';
+import { parseSync } from '../src-js/index.js';
 
 function parseSyncLazy(filename, code, options = null) {
   return parseSync(filename, code, { ...options, experimentalLazy: true });
diff --git a/napi/parser/test/parse-raw-common.mjs b/napi/parser/test/parse-raw-common.js
similarity index 100%
rename from napi/parser/test/parse-raw-common.mjs
rename to napi/parser/test/parse-raw-common.js
diff --git a/napi/parser/test/parse-raw-worker.mjs b/napi/parser/test/parse-raw-worker.js
similarity index 99%
rename from napi/parser/test/parse-raw-worker.mjs
rename to napi/parser/test/parse-raw-worker.js
index b839604edf89a..93f505c7ff5d2 100644
--- a/napi/parser/test/parse-raw-worker.mjs
+++ b/napi/parser/test/parse-raw-worker.js
@@ -3,7 +3,7 @@
 import { readFile } from 'node:fs/promises';
 import { basename, join as pathJoin } from 'node:path';
 
-import { parseSync } from '../src-js/index.mjs';
+import { parseSync } from '../src-js/index.js';
 import {
   ACORN_TEST262_DIR_PATH,
   JSX_DIR_PATH,
@@ -19,8 +19,8 @@ import {
   TEST_TYPE_TS,
   TS_DIR_PATH,
   TS_ESTREE_DIR_PATH,
-} from './parse-raw-common.mjs';
-import { makeUnitsFromTest } from './typescript-make-units-from-test.mjs';
+} from './parse-raw-common.js';
+import { makeUnitsFromTest } from './typescript-make-units-from-test.js';
 
 // Run test case and return whether it passes.
 // This is the entry point when run as a worker.
diff --git a/napi/parser/test/parse-raw.test.ts b/napi/parser/test/parse-raw.test.ts
index aba12faa9465f..5110a24676db8 100644
--- a/napi/parser/test/parse-raw.test.ts
+++ b/napi/parser/test/parse-raw.test.ts
@@ -5,7 +5,7 @@ import { basename, join as pathJoin } from 'node:path';
 import Tinypool from 'tinypool';
 import { describe, expect, it } from 'vitest';
 
-import { parseAsync, parseSync, type TSTypeAliasDeclaration, type VariableDeclaration } from '../src-js/index.mjs';
+import { parseAsync, parseSync, type TSTypeAliasDeclaration, type VariableDeclaration } from '../src-js/index.js';
 
 import {
   ACORN_TEST262_DIR_PATH,
@@ -26,7 +26,7 @@ import {
   TS_ESTREE_DIR_PATH,
   TS_SHORT_DIR_PATH,
   TS_SNAPSHOT_PATH,
-} from './parse-raw-common.mjs';
+} from './parse-raw-common.js';
 
 const [describeLazy, itLazy] = process.env.RUN_LAZY_TESTS === 'true'
   ? [describe, it]
@@ -35,7 +35,7 @@ const [describeLazy, itLazy] = process.env.RUN_LAZY_TESTS === 'true'
 // Worker pool for running test cases.
 // Vitest provides parallelism across test files, but not across cases within a single test file.
 // So we run each case in a worker to achieve parallelism.
-const pool = new Tinypool({ filename: new URL('./parse-raw-worker.mjs', import.meta.url).href });
+const pool = new Tinypool({ filename: new URL('./parse-raw-worker.js', import.meta.url).href });
 
 let runCase;
 
@@ -46,7 +46,7 @@ async function runCaseInWorker(type, props) {
   // If test failed in worker, run it again in main thread with Vitest's `expect`,
   // to get a nice diff and stack trace
   if (!success) {
-    if (!runCase) ({ runCase } = await import('./parse-raw-worker.mjs'));
+    if (!runCase) ({ runCase } = await import('./parse-raw-worker.js'));
 
     type |= TEST_TYPE_PRETTY;
     await runCase({ type, props }, expect);
diff --git a/napi/parser/test/parse.test.ts b/napi/parser/test/parse.test.ts
index 3882a8ebdb41c..805cabea8aa5e 100644
--- a/napi/parser/test/parse.test.ts
+++ b/napi/parser/test/parse.test.ts
@@ -1,13 +1,13 @@
 import { Worker } from 'node:worker_threads';
 import { describe, expect, it, test } from 'vitest';
 
-import { parseAsync, parseSync } from '../src-js/index.mjs';
+import { parseAsync, parseSync } from '../src-js/index.js';
 import type {
   ExpressionStatement,
   ParserOptions,
   TSTypeAliasDeclaration,
   VariableDeclaration,
-} from '../src-js/index.mjs';
+} from '../src-js/index.js';
 
 describe('parse', () => {
   const code = '/* comment */ foo';
@@ -877,7 +877,7 @@ describe('error', () => {
 describe('worker', () => {
   it('should run', async () => {
     const code = await new Promise((resolve, reject) => {
-      const worker = new Worker('./test/worker.mjs');
+      const worker = new Worker('./test/worker.js');
       worker.on('error', (err) => {
         reject(err);
       });
diff --git a/napi/parser/test/parser.test-d.ts b/napi/parser/test/parser.test-d.ts
index 111318c1f4d3d..015d2bc21bd42 100644
--- a/napi/parser/test/parser.test-d.ts
+++ b/napi/parser/test/parser.test-d.ts
@@ -1,7 +1,7 @@
 import { assertType, describe, it } from 'vitest';
 
-import type { Node, Statement } from '../src-js/index.mjs';
-import { parseSync } from '../src-js/index.mjs';
+import type { Node, Statement } from '../src-js/index.js';
+import { parseSync } from '../src-js/index.js';
 
 describe('parse', () => {
   const code = '/* comment */ foo';
diff --git a/napi/parser/test/typescript-make-units-from-test.mjs b/napi/parser/test/typescript-make-units-from-test.js
similarity index 100%
rename from napi/parser/test/typescript-make-units-from-test.mjs
rename to napi/parser/test/typescript-make-units-from-test.js
diff --git a/napi/parser/test/visit.test.ts b/napi/parser/test/visit.test.ts
index 461c6d1da6829..f0f39c4373b60 100644
--- a/napi/parser/test/visit.test.ts
+++ b/napi/parser/test/visit.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest';
 
-import { parseSync, Visitor, visitorKeys, type VisitorObject } from '../src-js/index.mjs';
+import { parseSync, Visitor, visitorKeys, type VisitorObject } from '../src-js/index.js';
 
 describe('visit', () => {
   it('empty visitor', () => {
diff --git a/napi/parser/test/worker.js b/napi/parser/test/worker.js
new file mode 100644
index 0000000000000..756e0bf206013
--- /dev/null
+++ b/napi/parser/test/worker.js
@@ -0,0 +1,2 @@
+import { parseSync } from '../src-js/index.js';
+parseSync('test.js', '');
diff --git a/napi/parser/test/worker.mjs b/napi/parser/test/worker.mjs
deleted file mode 100644
index 862548a4fd255..0000000000000
--- a/napi/parser/test/worker.mjs
+++ /dev/null
@@ -1,2 +0,0 @@
-import { parseSync } from '../src-js/index.mjs';
-parseSync('test.js', '');
diff --git a/napi/parser/vitest.config.browser.mts b/napi/parser/vitest.config.browser.ts
similarity index 100%
rename from napi/parser/vitest.config.browser.mts
rename to napi/parser/vitest.config.browser.ts
diff --git a/napi/parser/vitest.config.mts b/napi/parser/vitest.config.ts
similarity index 100%
rename from napi/parser/vitest.config.mts
rename to napi/parser/vitest.config.ts
diff --git a/napi/playground/patch.mjs b/napi/playground/patch.mjs
index 82f46054e0879..cc74151012646 100644
--- a/napi/playground/patch.mjs
+++ b/napi/playground/patch.mjs
@@ -5,7 +5,7 @@ let data = fs.readFileSync(filename, 'utf-8');
 data = data.replace(
   `export const Oxc = __napiModule.exports.Oxc`,
   `
-import { jsonParseAst } from "../parser/src-js/wrap.mjs"
+import { jsonParseAst } from "../parser/src-js/wrap.js"
 
 export function Oxc() {
   const oxc = new __napiModule.exports.Oxc();
diff --git a/napi/playground/playground.wasi-browser.js b/napi/playground/playground.wasi-browser.js
index 9d3476781098b..2a649cfcb1054 100644
--- a/napi/playground/playground.wasi-browser.js
+++ b/napi/playground/playground.wasi-browser.js
@@ -58,7 +58,7 @@ const {
 export default __napiModule.exports
 export const Severity = __napiModule.exports.Severity
 
-import { jsonParseAst } from "../parser/src-js/wrap.mjs"
+import { jsonParseAst } from "../parser/src-js/wrap.js"
 
 export function Oxc() {
   const oxc = new __napiModule.exports.Oxc();
diff --git a/npm/oxlint/scripts/generate-packages.mjs b/npm/oxlint/scripts/generate-packages.js
similarity index 100%
rename from npm/oxlint/scripts/generate-packages.mjs
rename to npm/oxlint/scripts/generate-packages.js
diff --git a/tasks/ast_tools/src/generators/estree_visit.rs b/tasks/ast_tools/src/generators/estree_visit.rs
index 364af39825b11..e4e362dbd5469 100644
--- a/tasks/ast_tools/src/generators/estree_visit.rs
+++ b/tasks/ast_tools/src/generators/estree_visit.rs
@@ -40,19 +40,19 @@ impl Generator for ESTreeVisitGenerator {
 
         vec![
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/walk.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/walk.js"),
                 code: walk,
             },
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/keys.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/keys.js"),
                 code: visitor_keys,
             },
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/types.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/types.js"),
                 code: type_ids_map,
             },
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/visitor.d.mts"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/visit/visitor.d.ts"),
                 code: visitor_type,
             },
         ]
@@ -80,8 +80,8 @@ struct NodeKeys {
 /// * `Map` from node type name to node type ID.
 /// * Visitor type definition.
 fn generate(codegen: &Codegen) -> Codes {
-    // Run `napi/parser/scripts/visitor-keys.mjs` to get visitor keys from TS-ESLint
-    let script_path = codegen.root_path().join("napi/parser/scripts/visitor-keys.mjs");
+    // Run `napi/parser/scripts/visitor-keys.js` to get visitor keys from TS-ESLint
+    let script_path = codegen.root_path().join("napi/parser/scripts/visitor-keys.js");
 
     let output = Command::new("node")
         .arg(script_path)
diff --git a/tasks/ast_tools/src/generators/raw_transfer.rs b/tasks/ast_tools/src/generators/raw_transfer.rs
index 610cb72dd27d5..189ee3ba9da1a 100644
--- a/tasks/ast_tools/src/generators/raw_transfer.rs
+++ b/tasks/ast_tools/src/generators/raw_transfer.rs
@@ -65,19 +65,19 @@ impl Generator for RawTransferGenerator {
 
         vec![
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/deserialize/js.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/deserialize/js.js"),
                 code: js,
             },
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/deserialize/ts.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/deserialize/ts.js"),
                 code: ts,
             },
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/constants.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/constants.js"),
                 code: constants_js.clone(),
             },
             Output::Javascript {
-                path: format!("{OXLINT_APP_PATH}/src-js/generated/constants.mjs"),
+                path: format!("{OXLINT_APP_PATH}/src-js/generated/constants.js"),
                 code: constants_js,
             },
             Output::Rust {
diff --git a/tasks/ast_tools/src/generators/raw_transfer_lazy.rs b/tasks/ast_tools/src/generators/raw_transfer_lazy.rs
index e600e3a17172d..04bc20aadd6a2 100644
--- a/tasks/ast_tools/src/generators/raw_transfer_lazy.rs
+++ b/tasks/ast_tools/src/generators/raw_transfer_lazy.rs
@@ -37,15 +37,15 @@ impl Generator for RawTransferLazyGenerator {
 
         vec![
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/lazy/constructors.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/lazy/constructors.js"),
                 code: constructors,
             },
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/lazy/walk.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/lazy/walk.js"),
                 code: walkers,
             },
             Output::Javascript {
-                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/lazy/types.mjs"),
+                path: format!("{NAPI_PARSER_PACKAGE_PATH}/generated/lazy/types.js"),
                 code: node_type_ids_map,
             },
         ]
@@ -157,8 +157,8 @@ fn generate(
     let constructors = &state.constructors;
     #[rustfmt::skip]
     let constructors = format!("
-        import {{ constructorError, TOKEN }} from '../../src-js/raw-transfer/lazy-common.mjs';
-        import {{ NodeArray }} from '../../src-js/raw-transfer/node-array.mjs';
+        import {{ constructorError, TOKEN }} from '../../src-js/raw-transfer/lazy-common.js';
+        import {{ NodeArray }} from '../../src-js/raw-transfer/node-array.js';
 
         const textDecoder = new TextDecoder('utf-8', {{ ignoreBOM: true }}),
             decodeStr = textDecoder.decode.bind(textDecoder),
@@ -173,7 +173,7 @@ fn generate(
     let walked_constructor_names = &state.walked_constructor_names;
     #[rustfmt::skip]
     let walkers = format!("
-        import {{ {walked_constructor_names} }} from './constructors.mjs';
+        import {{ {walked_constructor_names} }} from './constructors.js';
 
         export {{ walkProgram }};
 
diff --git a/tasks/benchmark/benches/parser_napi.rs b/tasks/benchmark/benches/parser_napi.rs
index c33de1011d596..a42a07bf592dd 100644
--- a/tasks/benchmark/benches/parser_napi.rs
+++ b/tasks/benchmark/benches/parser_napi.rs
@@ -15,8 +15,8 @@ struct BenchResult {
 /// It's a workaround for CodSpeed's measurement of JS + NAPI being wildly inaccurate:
 /// https://github.com/CodSpeedHQ/action/issues/96
 /// So instead in CI we run the actual benchmark without CodSpeed's instrumentation
-/// (see `.github/workflows/benchmark.yml` and `napi/parser/parse.bench.mjs`).
-/// `parse.bench.mjs` writes the results of the benchmarks to a file `results.json`.
+/// (see `.github/workflows/benchmark.yml` and `napi/parser/bench.bench.js`).
+/// `bench.bench.js` writes the results of the benchmarks to a file `results.json`.
 /// This pseudo-benchmark reads that file and just performs meaningless calculations in a loop
 /// the number of times required to take same amount of time as the original benchmark.
 fn bench_parser_napi(criterion: &mut Criterion) {