Move to TypeScript (#3830)

This moves our JS file to use TS instead, which allows us to use a proper linter to check the code.
All related files where moved out from the root in a dedicated folder to avoid polluting the Rust environment.

.github/dependabot.yaml

@@ -0,0 +1,11 @@
+version: 2
+
+updates:
+  - package-ecosystem: npm
+    directory: src/platform_impl/web/script
+    schedule:
+        interval: daily
+    groups:
+        github-actions:
+            patterns:
+                - '*'

.github/workflows/ci.yml

@@ -243,17 +243,36 @@ jobs:
         log-level: error
         arguments: --all-features --target ${{ matrix.platform.target }}
 
+  eslint:
+    name: ESLint
+
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./src/platform_impl/web/script
+
+    steps:
+      - uses: taiki-e/checkout-action@v1
+      - name: Setup NPM
+        run: npm install
+      - name: Run ESLint
+        run: npx eslint
+
   swc:
     name: Minimize JavaScript
+
     runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./src/platform_impl/web/script
 
     steps:
       - uses: taiki-e/checkout-action@v1
       - name: Install SWC
         run: sudo npm i -g @swc/cli
       - name: Run SWC
         run: |
-          swc src/platform_impl/web/web_sys/worker.js -o src/platform_impl/web/web_sys/worker.min.js
+          swc . --ignore node_modules,**/*.d.ts --only **/*.ts -d . --out-file-extension min.js
       - name: Check for diff
         run: |
           [[ -z $(git status -s) ]]

.gitignore

@@ -5,3 +5,6 @@ rls/
 *~
 #*#
 .DS_Store
+# NPM package used to run ESLint.
+/src/platform_impl/web/script/node_modules
+/src/platform_impl/web/script/package-lock.json

.swcrc → src/platform_impl/web/script/.swcrc

@@ -1,6 +1,13 @@
 {
+	"module": {
+		"type": "es6"
+	},
+	"isModule": true,
 	"minify": true,
 	"jsc": {
+		"parser": {
+			"syntax": "typescript"
+		},
 		"target": "es2022",
 		"minify": {
 			"compress": {

src/platform_impl/web/script/eslint.config.mjs

@@ -0,0 +1,32 @@
+import eslint from '@eslint/js'
+import tseslint from 'typescript-eslint'
+import globals from 'globals'
+
+export default tseslint.config(
+	{
+		ignores: ['**/*.min.js', 'eslint.config.mjs'],
+	},
+	eslint.configs.recommended,
+	...tseslint.configs.strictTypeChecked,
+	...tseslint.configs.stylisticTypeChecked,
+	{
+		languageOptions: {
+			parserOptions: {
+				ecmaVersion: 'latest',
+				project: ['tsconfig.json'],
+				sourceType: 'module',
+			},
+			globals: {
+				...globals.browser,
+			},
+		},
+		rules: {
+			'@typescript-eslint/no-confusing-void-expression': [
+				'error',
+				{
+					ignoreArrowShorthand: true,
+				},
+			],
+		},
+	}
+)

src/platform_impl/web/script/package.json

@@ -0,0 +1,9 @@
+{
+	"devDependencies": {
+		"@eslint/js": "^9",
+		"@types/eslint__js": "^8",
+		"eslint": "^8",
+		"typescript": "^5",
+		"typescript-eslint": "^7"
+	}
+}

src/platform_impl/web/script/scheduler.d.ts

@@ -0,0 +1,12 @@
+declare global {
+	// eslint-disable-next-line no-var
+	var scheduler: Scheduler
+}
+
+export interface Scheduler {
+	postTask<T>(callback: () => T | PromiseLike<T>, options?: SchedulerPostTaskOptions): Promise<T>
+}
+
+export interface SchedulerPostTaskOptions {
+	delay?: number
+}

src/platform_impl/web/script/tsconfig.json

@@ -0,0 +1,14 @@
+{
+	"compilerOptions": {
+		"target": "ESNext",
+		"allowUnreachableCode": false,
+		"allowUnusedLabels": false,
+		"exactOptionalPropertyTypes": true,
+		"noImplicitOverride": true,
+		"noPropertyAccessFromIndexSignature": true,
+		"noUncheckedIndexedAccess": true,
+		"noUnusedLocals": true,
+		"noUnusedParameters": true,
+		"strict": true,
+	}
+}

src/platform_impl/web/script/worker.ts

@@ -0,0 +1,10 @@
+onmessage = (event) => {
+	const [port, timeout] = event.data as [MessagePort, number]
+	const f = () => port.postMessage(undefined)
+
+	if ('scheduler' in globalThis) {
+		void globalThis.scheduler.postTask(f, { delay: timeout })
+	} else {
+		setTimeout(f, timeout)
+	}
+}

src/platform_impl/web/web_sys/schedule.rs

@@ -175,7 +175,7 @@ impl Schedule {
         F: 'static + FnMut(),
     {
         thread_local! {
-            static URL: ScriptUrl = ScriptUrl::new(include_str!("worker.min.js"));
+            static URL: ScriptUrl = ScriptUrl::new(include_str!("../script/worker.min.js"));
             static WORKER: Worker = URL.with(|url| Worker::new(&url.0)).expect("`new Worker()` is not expected to fail with a local script");
         }