From 39094de1fc3cd1ae2bd3080a02024d0b3b33eade Mon Sep 17 00:00:00 2001
From: Tommy Nguyen <4123478+tido64@users.noreply.github.com>
Date: Thu, 9 Jan 2025 16:01:48 +0100
Subject: [PATCH] chore: convert internal scripts to `.mts` (#2367)

---
 .github/workflows/build.yml                   |  4 +-
 .../reacttestapp/manifest/Manifest.kt         |  2 +-
 eslint.config.js                              | 18 ++--
 ios/ReactTestApp/Manifest.swift               |  2 +-
 package.json                                  | 24 ++---
 scripts/build/{affected.ts => affected.mts}   |  0
 ...st-docs.mjs => generate-manifest-docs.mts} | 18 ++--
 ...ate-manifest.mjs => generate-manifest.mts} | 61 +++++++------
 ...enerate-schema.mjs => generate-schema.mts} | 35 +++++---
 scripts/internal/{pack.mjs => pack.mts}       |  5 +-
 ...-viewfinder.mjs => prepare-viewfinder.mts} |  8 +-
 .../{release-notes.mjs => release-notes.mts}  | 26 +++---
 ...eact-version.mjs => set-react-version.mts} | 90 +++++++------------
 scripts/internal/{test.mjs => test.mts}       | 15 +---
 .../{react-native.mjs => react-native.mts}    |  8 +-
 .../{test-apple.mjs => test-apple.mts}        | 15 ++--
 .../testing/{test-e2e.mjs => test-e2e.mts}    | 23 ++---
 .../{test-matrix.mjs => test-matrix.mts}      | 66 +++++---------
 scripts/types.ts                              | 31 +------
 test/configure/updatePackageManifest.test.ts  |  4 +-
 tsconfig.json                                 |  1 +
 windows/Shared/Manifest.h                     |  2 +-
 22 files changed, 188 insertions(+), 270 deletions(-)
 rename scripts/build/{affected.ts => affected.mts} (100%)
 rename scripts/internal/{generate-manifest-docs.mjs => generate-manifest-docs.mts} (86%)
 rename scripts/internal/{generate-manifest.mjs => generate-manifest.mts} (85%)
 rename scripts/internal/{generate-schema.mjs => generate-schema.mts} (70%)
 rename scripts/internal/{pack.mjs => pack.mts} (91%)
 rename scripts/internal/{prepare-viewfinder.mjs => prepare-viewfinder.mts} (89%)
 rename scripts/internal/{release-notes.mjs => release-notes.mts} (83%)
 rename scripts/internal/{set-react-version.mjs => set-react-version.mts} (86%)
 rename scripts/internal/{test.mjs => test.mts} (79%)
 rename scripts/testing/{react-native.mjs => react-native.mts} (89%)
 rename scripts/testing/{test-apple.mjs => test-apple.mts} (88%)
 rename scripts/testing/{test-e2e.mjs => test-e2e.mts} (87%)
 rename scripts/testing/{test-matrix.mjs => test-matrix.mts} (87%)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 175963fc9..55b3c2e2c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -239,7 +239,7 @@ jobs:
       - name: react-native run-ios
         if: ${{ steps.affected.outputs.ios != '' }}
         run: |
-          ../scripts/testing/react-native.mjs run-ios
+          ../scripts/testing/react-native.mts run-ios
         working-directory: template-example
     timeout-minutes: 60
   android:
@@ -326,7 +326,7 @@ jobs:
       - name: react-native run-android
         if: ${{ steps.affected.outputs.android != '' }}
         run: |
-          ../scripts/testing/react-native.mjs run-android
+          ../scripts/testing/react-native.mts run-android
         working-directory: template-example
     timeout-minutes: 60
   macos:
diff --git a/android/app/src/main/java/com/microsoft/reacttestapp/manifest/Manifest.kt b/android/app/src/main/java/com/microsoft/reacttestapp/manifest/Manifest.kt
index 0625fd672..ab5abff65 100644
--- a/android/app/src/main/java/com/microsoft/reacttestapp/manifest/Manifest.kt
+++ b/android/app/src/main/java/com/microsoft/reacttestapp/manifest/Manifest.kt
@@ -1,4 +1,4 @@
-// This file was generated by generate-manifest.mjs.
+// This file was generated by generate-manifest.mts.
 // DO NOT MODIFY. ALL CHANGES WILL BE OVERWRITTEN.
 
 @file:Suppress("ktlint:standard:trailing-comma-on-declaration-site")
diff --git a/eslint.config.js b/eslint.config.js
index 4d4615bd9..056cbb3de 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -29,16 +29,16 @@ module.exports = [
   },
   {
     files: [
-      "scripts/internal/generate-manifest-docs.mjs",
-      "scripts/internal/generate-manifest.mjs",
-      "scripts/internal/generate-schema.mjs",
-      "scripts/internal/pack.mjs",
-      "scripts/internal/set-react-version.mjs",
-      "scripts/internal/test.mjs",
+      "scripts/internal/generate-manifest-docs.mts",
+      "scripts/internal/generate-manifest.mts",
+      "scripts/internal/generate-schema.mts",
+      "scripts/internal/pack.mts",
+      "scripts/internal/set-react-version.mts",
+      "scripts/internal/test.mts",
       "scripts/schema.mjs",
-      "scripts/testing/test-apple.mjs",
-      "scripts/testing/test-e2e.mjs",
-      "scripts/testing/test-matrix.mjs",
+      "scripts/testing/test-apple.mts",
+      "scripts/testing/test-e2e.mts",
+      "scripts/testing/test-matrix.mts",
       "scripts/utils/colors.mjs",
     ],
     rules: {
diff --git a/ios/ReactTestApp/Manifest.swift b/ios/ReactTestApp/Manifest.swift
index 33f0392fd..52a5299f1 100644
--- a/ios/ReactTestApp/Manifest.swift
+++ b/ios/ReactTestApp/Manifest.swift
@@ -1,4 +1,4 @@
-// This file was generated by generate-manifest.mjs.
+// This file was generated by generate-manifest.mts.
 // DO NOT MODIFY. ALL CHANGES WILL BE OVERWRITTEN.
 
 struct Component {
diff --git a/package.json b/package.json
index 2ba0f2f8d..144e924b1 100644
--- a/package.json
+++ b/package.json
@@ -67,24 +67,24 @@
   },
   "scripts": {
     "format:c": "clang-format -i $(git ls-files '*.cpp' '*.h' '*.m' '*.mm')",
-    "format:js": "prettier --write --log-level error $(git ls-files '*.[cm]js' '*.[jt]s' '*.tsx' '*.yml' 'CONTRIBUTING.md' 'README.md' 'test/**/*.json' ':!:.yarn/releases')",
+    "format:js": "prettier --write --log-level error $(git ls-files '*.[cm][jt]s' '*.[jt]s' '*.tsx' '*.yml' 'CONTRIBUTING.md' 'README.md' 'test/**/*.json' ':!:.yarn/releases')",
     "format:swift": "swiftformat $(git ls-files '*.swift')",
-    "generate:code": "node scripts/internal/generate-manifest.mjs",
-    "generate:docs": "node scripts/internal/generate-manifest-docs.mjs",
-    "generate:schema": "node scripts/internal/generate-schema.mjs",
+    "generate:code": "node --experimental-transform-types --no-warnings scripts/internal/generate-manifest.mts",
+    "generate:docs": "node --experimental-transform-types --no-warnings scripts/internal/generate-manifest-docs.mts",
+    "generate:schema": "node --experimental-transform-types --no-warnings scripts/internal/generate-schema.mts",
     "lint:commit": "git log --format='%s' origin/trunk..HEAD | tail -1 | npx @rnx-kit/commitlint-lite@2.0.0",
-    "lint:js": "eslint $(git ls-files '*.[cm]js' '*.[jt]s' '*.tsx' ':!:*.config.js' ':!:.yarn/releases') && tsc && tsc --project tsconfig.cjs.json",
+    "lint:js": "eslint $(git ls-files '*.[cm][jt]s' '*.[jt]s' '*.tsx' ':!:*.config.js' ':!:.yarn/releases') && tsc && tsc --project tsconfig.cjs.json",
     "lint:kt": "ktlint --relative 'android/app/src/**/*.kt'",
     "lint:rb": "bundle exec rubocop",
     "lint:swift": "swiftlint",
-    "prepack": "node scripts/internal/pack.mjs pre",
-    "postpack": "node scripts/internal/pack.mjs post",
-    "release-notes": "node scripts/internal/release-notes.mjs",
-    "set-react-version": "node scripts/internal/set-react-version.mjs",
-    "show-affected": "node --experimental-transform-types --no-warnings scripts/build/affected.ts",
-    "test": "node scripts/internal/test.mjs",
+    "prepack": "node --experimental-transform-types --no-warnings scripts/internal/pack.mts pre",
+    "postpack": "node --experimental-transform-types --no-warnings scripts/internal/pack.mts post",
+    "release-notes": "node --experimental-transform-types --no-warnings scripts/internal/release-notes.mts",
+    "set-react-version": "node --experimental-transform-types --no-warnings scripts/internal/set-react-version.mts",
+    "show-affected": "node --experimental-transform-types --no-warnings scripts/build/affected.mts",
+    "test": "node --experimental-transform-types --no-warnings scripts/internal/test.mts",
     "test:js": "node --experimental-transform-types --no-warnings --test $(git ls-files '*.test.ts')",
-    "test:matrix": "node scripts/testing/test-matrix.mjs",
+    "test:matrix": "node --experimental-transform-types --no-warnings scripts/testing/test-matrix.mts",
     "test:rb": "bundle exec ruby -Ilib:test -e \"Dir.glob('./test/test_*.rb').each { |file| require(file) }\""
   },
   "dependencies": {
diff --git a/scripts/build/affected.ts b/scripts/build/affected.mts
similarity index 100%
rename from scripts/build/affected.ts
rename to scripts/build/affected.mts
diff --git a/scripts/internal/generate-manifest-docs.mjs b/scripts/internal/generate-manifest-docs.mts
similarity index 86%
rename from scripts/internal/generate-manifest-docs.mjs
rename to scripts/internal/generate-manifest-docs.mts
index 27fe20c79..612bf6a22 100644
--- a/scripts/internal/generate-manifest-docs.mjs
+++ b/scripts/internal/generate-manifest-docs.mts
@@ -1,6 +1,7 @@
-// @ts-check
+// eslint-disable-next-line no-restricted-imports
+import type { SchemaObject } from "ajv";
 import * as path from "node:path";
-import { readDocumentation } from "./generate-schema.mjs";
+import { assertDefinition, readDocumentation } from "./generate-schema.mts";
 import { generateSchema } from "../schema.mjs";
 
 async function generateManifestDocs() {
@@ -9,12 +10,13 @@ async function generateManifestDocs() {
 
   /**
    * Renders the specified JSON object schema.
-   * @param {import("ajv").SchemaObject} definition
-   * @param {string[]} toc
-   * @param {string[]} lines
-   * @param {string} scope
    */
-  const render = (definition, toc, lines, scope = "") => {
+  const render = (
+    definition: SchemaObject,
+    toc: string[],
+    lines: string[],
+    scope = ""
+  ) => {
     if (Array.isArray(definition.allOf)) {
       for (const { $ref } of definition.allOf) {
         render(schema.$defs[$ref.replace("#/$defs/", "")], toc, lines, scope);
@@ -37,6 +39,8 @@ async function generateManifestDocs() {
     })();
 
     for (const [key, def] of Object.entries(definition.properties)) {
+      assertDefinition(def);
+
       const { description, markdownDescription, type } = def;
       const text = markdownDescription || description;
       if (!text) {
diff --git a/scripts/internal/generate-manifest.mjs b/scripts/internal/generate-manifest.mts
similarity index 85%
rename from scripts/internal/generate-manifest.mjs
rename to scripts/internal/generate-manifest.mts
index 833d387e1..9b6076c5e 100644
--- a/scripts/internal/generate-manifest.mjs
+++ b/scripts/internal/generate-manifest.mts
@@ -1,13 +1,25 @@
-// @ts-check
+// eslint-disable-next-line no-restricted-imports
+import type { SchemaObject } from "ajv";
 import * as fs from "node:fs/promises";
 import * as path from "node:path";
 import { URL, fileURLToPath } from "node:url";
 import { generateSchema } from "../schema.mjs";
+import { assertDefinition } from "./generate-schema.mts";
+
+type Language = {
+  options: {
+    indent: string;
+    level: number;
+    footer?: string;
+    header?: string;
+  };
+  arrayProperty: (name: string, type: string, required: boolean) => string;
+  objectProperty: (name: string, required: boolean) => string;
+  stringProperty: (name: string, required: boolean) => string;
+  structBegin: (name: string) => string;
+  structEnd: string;
+};
 
-/**
- * @import { SchemaObject } from "ajv";
- * @import { Language } from "../types.js";
- */
 const thisScript = fileURLToPath(import.meta.url);
 
 /**
@@ -15,7 +27,7 @@ const thisScript = fileURLToPath(import.meta.url);
  * @param {string} ref
  * @returns {string}
  */
-function typename(ref) {
+function typename(ref: string): string {
   const i = ref.lastIndexOf("/") + 1;
   return ref[i].toUpperCase() + ref.substring(i + 1);
 }
@@ -25,11 +37,10 @@ function typename(ref) {
  * @param {string} output
  * @returns {Language}
  */
-function getLanguage(output) {
+function getLanguage(output: string): Language {
   switch (path.extname(output)) {
     case ".h": {
-      /** @type {(type: string, required: boolean) => string} */
-      const nullable = (type, required) =>
+      const nullable = (type: string, required: boolean) =>
         required ? type : `std::optional<${type}>`;
       return {
         options: {
@@ -80,8 +91,7 @@ function getLanguage(output) {
     }
 
     case ".kt": {
-      /** @type {(required: boolean) => "" | "?"} */
-      const nullable = (required) => (required ? "" : "?");
+      const nullable = (required: boolean) => (required ? "" : "?");
       return {
         options: {
           indent: "    ",
@@ -110,8 +120,7 @@ function getLanguage(output) {
     }
 
     case ".swift": {
-      /** @type {(required: boolean) => "" | "?"} */
-      const nullable = (required) => (required ? "" : "?");
+      const nullable = (required: boolean) => (required ? "" : "?");
       return {
         options: {
           indent: "    ",
@@ -152,12 +161,12 @@ function getLanguage(output) {
 
 /**
  * Generates a data model from the specified schema definition.
- * @param {string} name
- * @param {SchemaObject} definition
- * @param {Language} lang
- * @returns {string[]}
  */
-function generateType(name, definition, lang) {
+function generateType(
+  name: string,
+  definition: SchemaObject,
+  lang: Language
+): string[] {
   const { indent, level } = lang.options;
   const outer = indent.repeat(level);
   const inner = indent.repeat(level + 1);
@@ -166,6 +175,8 @@ function generateType(name, definition, lang) {
 
   const { properties, required = [] } = definition;
   Object.entries(properties).forEach(([name, prop]) => {
+    assertDefinition(prop);
+
     const isRequired = required.includes(name);
     switch (prop.type) {
       case "array":
@@ -188,10 +199,8 @@ function generateType(name, definition, lang) {
 
 /**
  * Generates manifest data models and writes them to specified path.
- * @param {SchemaObject} schema
- * @param {string} output
  */
-async function generate(schema, output) {
+async function generate(schema: SchemaObject, output: string) {
   const lang = getLanguage(output);
   const lines = [
     `// This file was generated by ${path.basename(thisScript)}.`,
@@ -204,15 +213,9 @@ async function generate(schema, output) {
   }
 
   Object.entries(schema.$defs).forEach(([key, definition]) => {
+    assertDefinition(definition);
     if (!("exclude-from-codegen" in definition)) {
-      lines.push(
-        ...generateType(
-          typename(key),
-          /** @type {SchemaObject} */ (definition),
-          lang
-        ),
-        ""
-      );
+      lines.push(...generateType(typename(key), definition, lang), "");
     }
     return lines;
   });
diff --git a/scripts/internal/generate-schema.mjs b/scripts/internal/generate-schema.mts
similarity index 70%
rename from scripts/internal/generate-schema.mjs
rename to scripts/internal/generate-schema.mts
index f32e5eb30..5ba3b64f2 100644
--- a/scripts/internal/generate-schema.mjs
+++ b/scripts/internal/generate-schema.mts
@@ -1,27 +1,37 @@
-// @ts-check
+// eslint-disable-next-line no-restricted-imports
+import type { SchemaObject } from "ajv";
 import * as fs from "node:fs/promises";
 import * as os from "node:os";
 import * as path from "node:path";
 import { URL, fileURLToPath } from "node:url";
 import { isMain } from "../helpers.js";
 import { generateSchema } from "../schema.mjs";
+import type { Docs } from "../types.js";
 
-/** @import { Docs } from "../types.js"; */
+type Definition = SchemaObject & {
+  type: string;
+  description: string;
+  markdownDescription?: string;
+};
 
-/** @type {(str: string) => string} */
-const stripCarriageReturn =
+const stripCarriageReturn: (str: string) => string =
   os.EOL === "\r\n" ? (str) => str.replaceAll("\r", "") : (str) => str;
 
-/**
- * @returns {Promise<Partial<Docs>>}
- */
-export async function readDocumentation() {
-  /** @type {Partial<Docs>} */
-  const docs = {};
+export function assertDefinition(props: unknown): asserts props is Definition {
+  if (
+    !props ||
+    typeof props !== "object" ||
+    !("type" in props || "allOf" in props || "oneOf" in props)
+  ) {
+    throw new Error(`Invalid definition in schema: ${JSON.stringify(props)}`);
+  }
+}
+
+export async function readDocumentation(): Promise<Partial<Docs>> {
+  const docs: Partial<Docs> = {};
   const docsDir = fileURLToPath(new URL("../../docs", import.meta.url));
 
-  /** @type {(keyof Docs)[]} */
-  const keys = [
+  const keys: (keyof Docs)[] = [
     "introduction",
     "bundleRoot",
     "components",
@@ -67,6 +77,7 @@ if (isMain(import.meta.url)) {
     .then((docs) => generateSchema(docs))
     .then((schema) => {
       for (const def of Object.values(schema.$defs)) {
+        assertDefinition(def);
         delete def["exclude-from-codegen"];
       }
       return stripCarriageReturn(JSON.stringify(schema, undefined, 2)) + "\n";
diff --git a/scripts/internal/pack.mjs b/scripts/internal/pack.mts
similarity index 91%
rename from scripts/internal/pack.mjs
rename to scripts/internal/pack.mts
index 590cce94c..68818d679 100644
--- a/scripts/internal/pack.mjs
+++ b/scripts/internal/pack.mts
@@ -1,4 +1,3 @@
-// @ts-check
 import * as fs from "node:fs";
 import * as path from "node:path";
 
@@ -6,10 +5,8 @@ const files = ["example/.gitignore", "example/windows/.gitignore"];
 
 /**
  * Renames `.dotfile` to `_dotfile`.
- * @param {string} p
- * @returns {string}
  */
-function renameDotFile(p) {
+function renameDotFile(p: string): string {
   return path.join(path.dirname(p), "_" + path.basename(p).substring(1));
 }
 
diff --git a/scripts/internal/prepare-viewfinder.mjs b/scripts/internal/prepare-viewfinder.mts
similarity index 89%
rename from scripts/internal/prepare-viewfinder.mjs
rename to scripts/internal/prepare-viewfinder.mts
index 294dd0f95..67d7611b3 100755
--- a/scripts/internal/prepare-viewfinder.mjs
+++ b/scripts/internal/prepare-viewfinder.mts
@@ -1,5 +1,4 @@
-#!/usr/bin/env node
-// @ts-check
+#!/usr/bin/env -S node --experimental-transform-types --no-warnings
 
 import { spawnSync } from "node:child_process";
 import * as fs from "node:fs";
@@ -40,11 +39,8 @@ function configureAppManifest() {
 
 /**
  * Runs the specified command.
- * @param {string} command
- * @param {string[]} args
- * @param {Record<string, unknown>=} options
  */
-function $(command, args, options) {
+function $(command: string, args: string[], options?: Record<string, unknown>) {
   const { error, status } = spawnSync(command, args, {
     cwd: PROJECT_ROOT,
     stdio: "inherit",
diff --git a/scripts/internal/release-notes.mjs b/scripts/internal/release-notes.mts
similarity index 83%
rename from scripts/internal/release-notes.mjs
rename to scripts/internal/release-notes.mts
index 5bd446a43..b5f78033e 100644
--- a/scripts/internal/release-notes.mjs
+++ b/scripts/internal/release-notes.mts
@@ -1,25 +1,20 @@
 /**
  * This script is only used to help write release announcements.
  */
-// @ts-check
 // @ts-expect-error Could not find a declaration file for module
 import { generateNotes } from "@semantic-release/release-notes-generator";
 import { spawn } from "node:child_process";
 import * as path from "node:path";
 import { URL, fileURLToPath } from "node:url";
 import { readJSONFile } from "../helpers.js";
+import type { Manifest } from "../types.js";
 
-/** @typedef {import("../types.js").Manifest} Manifest */
-
-/**
- * @param {string} output
- * @param {string} lastRelease
- * @param {string} nextRelease
- * @returns {string}
- */
-function reformat(output, lastRelease, nextRelease) {
-  /** @type {[RegExp, string][]} */
-  const replacements = [
+function reformat(
+  output: string,
+  lastRelease: string,
+  nextRelease: string
+): string {
+  const replacements: [RegExp, string][] = [
     [/^# .*/m, `📣 react-native-test-app ${nextRelease}`],
     [/^### .*/m, `Other fixes since ${lastRelease}:`],
     [/^\* \*\*android:\*\*/gm, "* **Android:**"],
@@ -40,7 +35,7 @@ function reformat(output, lastRelease, nextRelease) {
 
 function repositoryUrl() {
   const p = fileURLToPath(new URL("../../package.json", import.meta.url));
-  const manifest = /** @type {Manifest} */ (readJSONFile(p));
+  const manifest = readJSONFile<Manifest>(p);
   return manifest.repository?.url;
 }
 
@@ -48,7 +43,7 @@ function repositoryUrl() {
  * @param {string} lastRelease
  * @param {string} nextRelease
  */
-function main(lastRelease, nextRelease) {
+function main(lastRelease: string, nextRelease: string): void {
   const args = [
     "log",
     `--pretty=format:{ "hash": "%H", "message": "%s" }`,
@@ -86,8 +81,7 @@ function main(lastRelease, nextRelease) {
       cwd: process.cwd(),
     };
 
-    /** @type {Promise<string>} */
-    const releaseNotes = generateNotes({}, context);
+    const releaseNotes: Promise<string> = generateNotes({}, context);
     releaseNotes
       .then((output) => reformat(output, lastRelease, nextRelease))
       .then((output) => console.log(output));
diff --git a/scripts/internal/set-react-version.mjs b/scripts/internal/set-react-version.mts
similarity index 86%
rename from scripts/internal/set-react-version.mjs
rename to scripts/internal/set-react-version.mts
index 25a6c7656..f93690759 100644
--- a/scripts/internal/set-react-version.mjs
+++ b/scripts/internal/set-react-version.mts
@@ -1,5 +1,3 @@
-// @ts-check
-
 /**
  * Reminder that this script is meant to be runnable without installing
  * dependencies. It can therefore not rely on any external libraries.
@@ -15,42 +13,30 @@ import {
   toVersionNumber,
   v,
 } from "../helpers.js";
+import type { Manifest } from "../types.js";
 import { fetchPackageMetadata, npmRegistryBaseURL } from "../utils/npm.mjs";
 
-/** @import { Manifest } from "../types.js"; */
-/**
- * @template T
- * @typedef {{ [P in keyof T]: Required<NonNullable<T[P]>> }} RequiredObject<T>
- */
-
 const VALID_TAGS = ["canary-macos", "canary-windows", "nightly"];
 
 /**
  * Returns whether specified string is a valid version number.
- * @param {string} v
- * @return {boolean}
  */
-function isValidVersion(v) {
+function isValidVersion(v: string): boolean {
   return /^\d+\.\d+$/.test(v) || VALID_TAGS.includes(v);
 }
 
 /**
  * Type-safe `Object.keys()`
- * @template {Record<string, unknown>} T
- * @param {T} obj
- * @returns {(keyof T)[]}
  */
-function keys(obj) {
-  return /** @type {(keyof T)[]} */ (Object.keys(obj));
+function keys<T extends Record<string, unknown>>(obj: T): (keyof T)[] {
+  return Object.keys(obj) as (keyof T)[];
 }
 
-/**
- * @param {string} filename
- * @param {string | RegExp} searchValue
- * @param {string} replaceValue
- * @returns {Promise<void>}
- */
-function searchReplaceInFile(filename, searchValue, replaceValue) {
+function searchReplaceInFile(
+  filename: string,
+  searchValue: string | RegExp,
+  replaceValue: string
+): Promise<void> {
   const current = readTextFile(filename);
   const updated = current.replace(searchValue, replaceValue);
   return updated === current
@@ -83,10 +69,12 @@ function disableWebStorage() {
 
 /**
  * Infer the React Native version an out-of-tree platform package is based on.
- * @param {Manifest} manifest
- * @returns {string}
  */
-function inferReactNativeVersion({ name, version, dependencies = {} }) {
+function inferReactNativeVersion({
+  name,
+  version,
+  dependencies = {},
+}: Manifest): string {
   const codegenVersion = dependencies["@react-native/codegen"];
   if (!codegenVersion) {
     throw new Error(
@@ -102,11 +90,8 @@ function inferReactNativeVersion({ name, version, dependencies = {} }) {
 
 /**
  * Fetches package information.
- * @param {string} pkg
- * @param {string} version
- * @return {Promise<Manifest>}
  */
-function fetchPackageInfo(pkg, version) {
+function fetchPackageInfo(pkg: string, version: string): Promise<Manifest> {
   return fetchPackageMetadata(pkg)
     .then(({ ["dist-tags"]: distTags, versions }) => {
       const tags = [version, version + "-stable", "v" + version + "-stable"];
@@ -131,7 +116,7 @@ function fetchPackageInfo(pkg, version) {
       }
       return fetch(npmRegistryBaseURL + pkg + "/" + foundVersion);
     })
-    .then((res) => res?.json() ?? /** @type {Manifest} */ ({}))
+    .then((res) => res?.json() ?? ({} as Manifest))
     .then(({ version, dependencies = {}, peerDependencies = {} }) => {
       return { version, dependencies, peerDependencies };
     });
@@ -139,9 +124,8 @@ function fetchPackageInfo(pkg, version) {
 
 /**
  * Fetches the latest react-native-windows@canary information via NuGet.
- * @return {Promise<Manifest>}
  */
-function fetchReactNativeWindowsCanaryInfoViaNuGet() {
+function fetchReactNativeWindowsCanaryInfoViaNuGet(): Promise<Manifest> {
   const rnwNuGetFeed =
     "https://pkgs.dev.azure.com/ms/react-native/_packaging/react-native-public/nuget/v3/index.json";
   return fetch(rnwNuGetFeed)
@@ -188,14 +172,11 @@ function fetchReactNativeWindowsCanaryInfoViaNuGet() {
 
 /**
  * Returns an object with common dependencies.
- * @param {string} v
- * @param {Manifest} manifest
- * @return {Promise<Record<string, string | undefined>>}
  */
 async function resolveCommonDependencies(
-  v,
-  { dependencies = {}, peerDependencies = {} }
-) {
+  v: string,
+  { dependencies = {}, peerDependencies = {} }: Manifest
+): Promise<Record<string, string | undefined>> {
   const [rnBabelPresetVersion, rnMetroConfigVersion, metroBabelPresetVersion] =
     await (async () => {
       if (["^", "canary", "nightly"].some((tag) => v.includes(tag))) {
@@ -263,12 +244,12 @@ async function resolveCommonDependencies(
 
 /**
  * Returns a profile for specified version.
- * @param {string} v
- * @param {boolean} coreOnly
- * @return {Promise<Record<string, string | undefined>>}
  */
-async function getProfile(v, coreOnly) {
-  const manifest = /** @type {Manifest} */ (readJSONFile("package.json"));
+async function getProfile(
+  v: string,
+  coreOnly: boolean
+): Promise<Record<string, string | undefined>> {
+  const manifest = readJSONFile<Manifest>("package.json");
   const visionos = manifest.defaultPlatformPackages?.["visionos"];
   if (!visionos) {
     throw new Error("Missing platform package for visionOS");
@@ -329,8 +310,7 @@ async function getProfile(v, coreOnly) {
       const reactNative = await versions.core;
       const commonDeps = await resolveCommonDependencies(v, reactNative);
 
-      /** @type {(manifest: Manifest) => string | undefined} */
-      const getVersion = ({ version }) => version;
+      const getVersion = ({ version }: Manifest) => version;
       return {
         ...commonDeps,
         "react-native": reactNative.version,
@@ -344,21 +324,20 @@ async function getProfile(v, coreOnly) {
 
 /**
  * Sets specified React Native version.
- * @param {string} version
- * @param {boolean} coreOnly
- * @param {Record<string, string>} [overrides]
- * @return {Promise<void>}
  */
-export async function setReactVersion(version, coreOnly, overrides = {}) {
-  /** @type {fs.FileHandle | undefined} */
-  let fd;
+export async function setReactVersion(
+  version: string,
+  coreOnly: boolean,
+  overrides: Record<string, string> = {}
+): Promise<void> {
+  let fd: fs.FileHandle | undefined;
   try {
     const profile = { ...(await getProfile(version, coreOnly)), ...overrides };
     console.dir(profile, { depth: null });
 
     const manifests = ["package.json", "example/package.json"];
     for (const manifestPath of manifests) {
-      const manifest = /** @type {Manifest} */ (readJSONFile(manifestPath));
+      const manifest = readJSONFile<Manifest>(manifestPath);
       const { dependencies, devDependencies, resolutions = {} } = manifest;
       if (!devDependencies) {
         throw new Error("Expected 'devDependencies' to be declared");
@@ -424,8 +403,7 @@ if (isMain(import.meta.url)) {
     );
     process.exitCode = 1;
   } else {
-    const { "core-only": coreOnly, overrides } =
-      /** @type {RequiredObject<typeof values>} */ (values);
+    const { "core-only": coreOnly, overrides } = values;
     setReactVersion(version, coreOnly, JSON.parse(overrides)).then(() => {
       const numVersion = VALID_TAGS.includes(version)
         ? Number.MAX_SAFE_INTEGER
diff --git a/scripts/internal/test.mjs b/scripts/internal/test.mts
similarity index 79%
rename from scripts/internal/test.mjs
rename to scripts/internal/test.mts
index 31ce67d6a..6c66107c9 100644
--- a/scripts/internal/test.mjs
+++ b/scripts/internal/test.mts
@@ -1,11 +1,8 @@
-// @ts-check
 import { spawnSync } from "node:child_process";
 
-/**
- * @param {string[]} files
- * @returns {"ruby" | "typescript" | undefined}
- */
-function getTarget(files) {
+type Language = "ruby" | "typescript";
+
+function getTarget(files: string[]): Language | undefined {
   if (files.some((file) => file.endsWith(".rb"))) {
     return "ruby";
   } else if (files.some((file) => file.endsWith(".ts"))) {
@@ -15,11 +12,7 @@ function getTarget(files) {
   }
 }
 
-/**
- * @param {string} command
- * @param {string[]} args
- */
-function testWith(command, args) {
+function testWith(command: string, args: string[]): void {
   const result = spawnSync(command, args, { stdio: "inherit" });
   process.exitCode = result.status ?? 1;
 }
diff --git a/scripts/testing/react-native.mjs b/scripts/testing/react-native.mts
similarity index 89%
rename from scripts/testing/react-native.mjs
rename to scripts/testing/react-native.mts
index 503944bfe..2fa216c60 100755
--- a/scripts/testing/react-native.mjs
+++ b/scripts/testing/react-native.mts
@@ -1,15 +1,13 @@
-#!/usr/bin/env node
-// @ts-check
+#!/usr/bin/env -S node --experimental-transform-types --no-warnings
+
 import { spawnSync } from "node:child_process";
 
 const DEVICE_ID = "T-800";
 
 /**
  * Runs the specified command.
- * @param {RegExp} successPattern The string to look for
- * @param  {...any} args The command to run and its arguments
  */
-function run(successPattern, ...args) {
+function run(successPattern: RegExp, ...args: readonly string[]) {
   const { stderr } = spawnSync("yarn", args, { encoding: "utf-8" });
   if (!successPattern.test(stderr)) {
     throw new Error(stderr);
diff --git a/scripts/testing/test-apple.mjs b/scripts/testing/test-apple.mts
similarity index 88%
rename from scripts/testing/test-apple.mjs
rename to scripts/testing/test-apple.mts
index 187d3d125..5f31e2181 100644
--- a/scripts/testing/test-apple.mjs
+++ b/scripts/testing/test-apple.mts
@@ -1,5 +1,3 @@
-// @ts-check
-
 /**
  * Reminder that this script is meant to be runnable without installing
  * dependencies. It can therefore not rely on any external libraries.
@@ -8,9 +6,8 @@ import { spawnSync } from "node:child_process";
 import * as fs from "node:fs";
 import { URL, fileURLToPath } from "node:url";
 import { memo, readTextFile } from "../helpers.js";
-import { $ } from "./test-e2e.mjs";
-
-/** @import { BuildConfig } from "../types.js"; */
+import type { BuildConfig } from "../types.js";
+import { $ } from "./test-e2e.mts";
 
 export const getIOSSimulatorName = memo(() => {
   const wdioConfig = new URL(
@@ -39,10 +36,12 @@ export const getIOSSimulatorName = memo(() => {
 
 /**
  * Configures `Podfile` and invokes `pod install`.
- * @param {Required<BuildConfig>} config
- * @returns {Promise<void>}
  */
-export function installPods({ platform, engine, variant }) {
+export function installPods({
+  platform,
+  engine,
+  variant,
+}: Required<BuildConfig>): Promise<void> {
   const podfile = `${platform}/Podfile`;
   let content = readTextFile(podfile);
 
diff --git a/scripts/testing/test-e2e.mjs b/scripts/testing/test-e2e.mts
similarity index 87%
rename from scripts/testing/test-e2e.mjs
rename to scripts/testing/test-e2e.mts
index 5f2bc422c..f8f073d3e 100644
--- a/scripts/testing/test-e2e.mjs
+++ b/scripts/testing/test-e2e.mts
@@ -1,5 +1,3 @@
-// @ts-check
-
 /**
  * Reminder that this script is meant to be runnable without installing
  * dependencies. It can therefore not rely on any external libraries.
@@ -10,10 +8,8 @@ import { isMain } from "../helpers.js";
 
 /**
  * Invokes a shell command with optional arguments.
- * @param {string} command
- * @param {...string} args
  */
-export function $(command, ...args) {
+export function $(command: string, ...args: string[]) {
   const { status } = spawnSync(command, args, { stdio: "inherit" });
   if (status !== 0) {
     throw new Error(
@@ -25,11 +21,8 @@ export function $(command, ...args) {
 /**
  * Invokes a shell command with optional arguments. Similar {@link $}, but
  * captures and returns stdout/stderr.
- * @param {string} command
- * @param {...string} args
- * @returns {string}
  */
-export function $$(command, ...args) {
+export function $$(command: string, ...args: string[]): string {
   const { status, stderr, stdout } = spawnSync(command, args, {
     stdio: ["ignore", "pipe", "pipe"],
     encoding: "utf-8",
@@ -45,15 +38,13 @@ export function $$(command, ...args) {
 
 /**
  * Ensures Appium is available.
- * @returns {Promise<void>}
  */
-function ensureAppiumAvailable() {
+function ensureAppiumAvailable(): Promise<void> {
   return new Promise((resolve, reject) => {
     const socket = new Socket();
     socket.setTimeout(60 * 1000);
 
-    /** @type {(e: Error) => void} */
-    const onError = (e) => {
+    const onError = (e: Error) => {
       socket.destroy();
       reject(new Error(`Could not connect to Appium server: ${e}`));
     };
@@ -95,11 +86,7 @@ function prepareAndroid(androidHome = process.env["ANDROID_HOME"]) {
   $(adb, "install", "android/app/build/outputs/apk/debug/app-debug.apk");
 }
 
-/**
- * @param {string} target
- * @param {string[]=} args
- */
-export async function test(target, args = []) {
+export async function test(target: string, args: string[] = []) {
   switch (target) {
     case "android":
       prepareAndroid();
diff --git a/scripts/testing/test-matrix.mjs b/scripts/testing/test-matrix.mts
similarity index 87%
rename from scripts/testing/test-matrix.mjs
rename to scripts/testing/test-matrix.mts
index b3e553ee3..abcde4b4d 100644
--- a/scripts/testing/test-matrix.mjs
+++ b/scripts/testing/test-matrix.mts
@@ -1,5 +1,3 @@
-// @ts-check
-
 /**
  * Reminder that this script is meant to be runnable without installing
  * dependencies. It can therefore not rely on any external libraries.
@@ -9,20 +7,23 @@ import * as fs from "node:fs";
 import { URL, fileURLToPath } from "node:url";
 import * as util from "node:util";
 import { readTextFile } from "../helpers.js";
-import { setReactVersion } from "../internal/set-react-version.mjs";
+import { setReactVersion } from "../internal/set-react-version.mts";
+import type { BuildConfig, TargetPlatform } from "../types.js";
 import { green, red, yellow } from "../utils/colors.mjs";
-import { getIOSSimulatorName, installPods } from "./test-apple.mjs";
-import { $, $$, test } from "./test-e2e.mjs";
+import { getIOSSimulatorName, installPods } from "./test-apple.mts";
+import { $, $$, test } from "./test-e2e.mts";
 
-/**
- * @import { BuildConfig, PlatformConfig, TargetPlatform } from "../types.js";
- */
+type PlatformConfig = {
+  name: string;
+  engines: ReadonlyArray<"hermes" | "jsc">;
+  isAvailable: (config: Required<BuildConfig>) => boolean;
+  prebuild: (config: Required<BuildConfig>) => Promise<void>;
+};
 
 const DEFAULT_PLATFORMS = ["android", "ios"];
-const TEST_VARIANTS = /** @type {const} */ (["paper", "fabric"]);
+const TEST_VARIANTS = ["paper", "fabric"] as const;
 
-/** @type {Record<TargetPlatform, PlatformConfig>} */
-const PLATFORM_CONFIG = {
+const PLATFORM_CONFIG: Record<TargetPlatform, PlatformConfig> = {
   android: {
     name: "Android",
     engines: ["hermes"],
@@ -76,10 +77,8 @@ function log(message = "", tag = TAG) {
 
 /**
  * Invokes `npm run` and redirects stdout/stderr to specified file.
- * @param {string} script
- * @param {string} logPath
  */
-function run(script, logPath) {
+function run(script: string, logPath: string) {
   const fd = fs.openSync(logPath, "a", 0o644);
   const proc = spawn(PACKAGE_MANAGER, ["run", script], {
     stdio: ["ignore", fd, fd],
@@ -87,10 +86,7 @@ function run(script, logPath) {
   return proc;
 }
 
-/**
- * @param {string} message
- */
-function showBanner(message) {
+function showBanner(message: string) {
   log();
   log(message, "┗━━▶");
   log("", "");
@@ -112,13 +108,8 @@ function startDevServer(logPath = "metro.server.log") {
   return run("start", logPath);
 }
 
-/**
- * @param {string[]} platforms
- * @returns {TargetPlatform[]}
- */
-function validatePlatforms(platforms) {
-  /** @type {TargetPlatform[]} */
-  const filtered = [];
+function validatePlatforms(platforms: string[]): TargetPlatform[] {
+  const filtered: TargetPlatform[] = [];
   for (const platform of platforms) {
     switch (platform) {
       case "android":
@@ -140,10 +131,7 @@ function validatePlatforms(platforms) {
   return filtered;
 }
 
-/**
- * @param {string[]} args
- */
-function parseArgs(args) {
+function parseArgs(args: string[]) {
   const { values, positionals } = util.parseArgs({
     args,
     options: {
@@ -200,9 +188,8 @@ function prestart() {
 
 /**
  * Invokes `react-native run-<platform>`.
- * @param {TargetPlatform} platform
  */
-function buildAndRun(platform) {
+function buildAndRun(platform: TargetPlatform) {
   switch (platform) {
     case "ios": {
       const simulator = getIOSSimulatorName();
@@ -216,10 +203,7 @@ function buildAndRun(platform) {
   }
 }
 
-/**
- * @param {BuildConfig} config
- */
-async function buildRunTest({ platform, variant }) {
+async function buildRunTest({ platform, variant }: BuildConfig) {
   const setup = PLATFORM_CONFIG[platform];
   if (!setup) {
     log(yellow(`⚠ Unknown platform: ${platform}`));
@@ -239,10 +223,7 @@ async function buildRunTest({ platform, variant }) {
   }
 }
 
-/**
- * @param {string} rootDir
- */
-function reset(rootDir) {
+function reset(rootDir: string) {
   log("Resetting...");
 
   process.chdir(rootDir);
@@ -266,10 +247,11 @@ function reset(rootDir) {
 
 /**
  * Invokes callback within the context of specified React Native version.
- * @param {string} version
- * @param {() => Promise<void>} action
  */
-async function withReactNativeVersion(version, action) {
+async function withReactNativeVersion(
+  version: string,
+  action: () => Promise<void>
+) {
   reset(rootDir);
 
   if (version) {
diff --git a/scripts/types.ts b/scripts/types.ts
index 7ddec26d4..e8e155da4 100644
--- a/scripts/types.ts
+++ b/scripts/types.ts
@@ -192,24 +192,6 @@ export type AppManifest = {
   };
 };
 
-/*************************
- * generate-manifest.mjs *
- *************************/
-
-export type Language = {
-  options: {
-    indent: string;
-    level: number;
-    footer?: string;
-    header?: string;
-  };
-  arrayProperty: (name: string, type: string, required: boolean) => string;
-  objectProperty: (name: string, required: boolean) => string;
-  stringProperty: (name: string, required: boolean) => string;
-  structBegin: (name: string) => string;
-  structEnd: string;
-};
-
 /**************
  * schema.mjs *
  **************/
@@ -262,9 +244,9 @@ export type Manifest = Partial<{
   defaultPlatformPackages: Record<string, PlatformPackage | undefined>;
 }>;
 
-/*************************
- * test-matrix.mjs *
- *************************/
+/***************************
+ * testing/test-matrix.mts *
+ ***************************/
 
 export type ApplePlatform = "ios" | "macos" | "visionos";
 export type TargetPlatform = ApplePlatform | "android" | "windows";
@@ -274,10 +256,3 @@ export type BuildConfig = {
   variant: "fabric" | "paper";
   engine?: "hermes" | "jsc";
 };
-
-export type PlatformConfig = {
-  name: string;
-  engines: ReadonlyArray<"hermes" | "jsc">;
-  isAvailable: (config: Required<BuildConfig>) => boolean;
-  prebuild: (config: Required<BuildConfig>) => Promise<void>;
-};
diff --git a/test/configure/updatePackageManifest.test.ts b/test/configure/updatePackageManifest.test.ts
index 0f70c9ad6..e6a09fb55 100644
--- a/test/configure/updatePackageManifest.test.ts
+++ b/test/configure/updatePackageManifest.test.ts
@@ -8,8 +8,8 @@ import { fs, setMockFiles } from "../fs.mock.ts";
 
 function getExampleManifest() {
   const p = new URL("../../example/package.json", import.meta.url);
-  const manifest = readJSONFile(p);
-  return manifest as Manifest;
+  const manifest = readJSONFile<Manifest>(p);
+  return manifest;
 }
 
 describe("updatePackageManifest()", () => {
diff --git a/tsconfig.json b/tsconfig.json
index 2bb989614..7a2637809 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -10,6 +10,7 @@
   },
   "include": [
     "**/*.mjs",
+    "**/*.mts",
     "**/*.ts"
   ]
 }
diff --git a/windows/Shared/Manifest.h b/windows/Shared/Manifest.h
index 568749634..c78b0dca8 100644
--- a/windows/Shared/Manifest.h
+++ b/windows/Shared/Manifest.h
@@ -1,4 +1,4 @@
-// This file was generated by generate-manifest.mjs.
+// This file was generated by generate-manifest.mts.
 // DO NOT MODIFY. ALL CHANGES WILL BE OVERWRITTEN.
 
 #pragma once