tools: lint typescript files

Makefile

@@ -1392,7 +1392,7 @@ format-md: tools/lint-md/node_modules/remark-parse/package.json ## Format the ma
 
 
 
-LINT_JS_TARGETS = eslint.config.mjs benchmark doc lib test tools
+LINT_JS_TARGETS = eslint.config.mjs benchmark doc lib test tools typings
 
 run-lint-js = tools/eslint/node_modules/eslint/bin/eslint.js --cache \
 	--max-warnings=0 --report-unused-disable-directives $(LINT_JS_TARGETS)

benchmark/eslint.config_partial.mjs

@@ -2,7 +2,7 @@ import { globals } from '../tools/eslint/eslint.config_utils.mjs';
 
 export default [
   {
-    files: ['benchmark/**/*.{js,mjs,cjs}'],
+    files: ['benchmark/**/*.{js,mjs,cjs,ts,mts,cts}'],
     languageOptions: {
       globals: {
         ...globals.node,

doc/api/typescript.md

@@ -147,7 +147,7 @@ This will result in [`ERR_UNSUPPORTED_TYPESCRIPT_SYNTAX`][] error:
 ```ts
 // This namespace is exporting a value
 namespace A {
-   export let x = 1
+   export const x = 1;
 }
 ```
 

doc/eslint.config_partial.mjs

@@ -9,7 +9,7 @@ const builtin = builtinModules.filter((name) => !name.startsWith('node:'));
 
 export default [
   {
-    files: ['doc/**/*.md/*.{js,mjs,cjs}'],
+    files: ['doc/**/*.md/*.{js,mjs,cjs,ts,cts,mts}'],
     rules: {
       // Ease some restrictions in doc examples.
       'no-restricted-properties': 'off',
@@ -22,6 +22,13 @@ export default [
           message: 'Use `node:` prefix.',
         },
       ],
+
+      // Typescript rules
+      '@typescript-eslint/no-unused-expressions': 'off',
+      '@typescript-eslint/no-unused-vars': 'off',
+      // Removed since it is used on how not to use examples.
+      '@typescript-eslint/no-namespace': 'off',
+
       'no-undef': 'off',
       'no-unused-expressions': 'off',
       'no-unused-vars': 'off',

eslint.config.mjs

@@ -23,6 +23,7 @@ const babelPluginSyntaxImportSource = resolveEslintTool('@babel/plugin-syntax-im
 const { default: jsdoc } = await importEslintTool('eslint-plugin-jsdoc');
 const { default: markdown } = await importEslintTool('eslint-plugin-markdown');
 const { default: stylisticJs } = await importEslintTool('@stylistic/eslint-plugin-js');
+const { default: tseslint } = await importEslintTool('typescript-eslint');
 
 nodeCore.RULES_DIR = fileURLToPath(new URL('./tools/eslint-rules', import.meta.url));
 
@@ -86,7 +87,7 @@ export default [
   js.configs.recommended,
   jsdoc.configs['flat/recommended'],
   {
-    files: ['**/*.{js,cjs}'],
+    files: ['**/*.{js,cjs,ts,cts}'],
     languageOptions: {
       // The default is `commonjs` but it's not supported by the Babel parser.
       sourceType: 'script',
@@ -352,7 +353,7 @@ export default [
     processor: 'markdown/markdown',
   },
   {
-    files: ['**/*.md/*.{js,cjs}'],
+    files: ['**/*.md/*.{js,cjs,ts,cts}'],
     languageOptions: {
       parserOptions: {
         ecmaFeatures: { impliedStrict: true },
@@ -369,38 +370,67 @@ export default [
     languageOptions: {
       sourceType: 'module',
     },
-    rules: { 'no-restricted-globals': [
-      'error',
-      {
-        name: '__filename',
-        message: 'Use import.meta.url instead.',
-      },
-      {
-        name: '__dirname',
-        message: 'Not available in ESM.',
-      },
-      {
-        name: 'exports',
-        message: 'Not available in ESM.',
-      },
-      {
-        name: 'module',
-        message: 'Not available in ESM.',
-      },
-      {
-        name: 'require',
-        message: 'Use import instead.',
-      },
-      {
-        name: 'Buffer',
-        message: "Import 'Buffer' instead of using the global.",
-      },
-      {
-        name: 'process',
-        message: "Import 'process' instead of using the global.",
-      },
-    ] },
+    rules: {
+      'no-restricted-globals': [
+        'error',
+        {
+          name: '__filename',
+          message: 'Use import.meta.url instead.',
+        },
+        {
+          name: '__dirname',
+          message: 'Not available in ESM.',
+        },
+        {
+          name: 'exports',
+          message: 'Not available in ESM.',
+        },
+        {
+          name: 'module',
+          message: 'Not available in ESM.',
+        },
+        {
+          name: 'require',
+          message: 'Use import instead.',
+        },
+        {
+          name: 'Buffer',
+          message: "Import 'Buffer' instead of using the global.",
+        },
+        {
+          name: 'process',
+          message: "Import 'process' instead of using the global.",
+        },
+      ],
+    },
+  },
+  // #region Typescript rules
+  {
+
+    files: ['**/*.{ts,mts,cts}'],
+    ...tseslint.configs.base,
+    rules: {
+      ...tseslint.configs.eslintRecommended.rules,
+      // Index 0 contains the base configuration,
+      // index 1 provides eslint-specific overrides,
+      // and index 2 includes the recommended rules.
+      ...tseslint.configs.recommended[2].rules,
+      // This is handled by 'no-restricted-globals'
+      '@typescript-eslint/no-require-imports': 'off',
+      // We use ignore comments throughout the codebase
+      '@typescript-eslint/ban-ts-comment': 'off',
+    },
   },
+  {
+    files: ['typings/**'],
+    rules: {
+      '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/no-empty-object-type': 'off',
+
+      'no-use-before-define': 'off',
+    },
+  },
+  // #endregion
   // #endregion
   // #region partials
   ...benchmarkConfig,

test/eslint.config_partial.mjs

@@ -7,7 +7,10 @@ import {
 
 export default [
   {
-    files: ['test/**/*.{js,mjs,cjs}'],
+    ignores: ['test/fixtures/**/*.{ts,mts,cts}'],
+  },
+  {
+    files: ['test/**/*.{js,mjs,cjs,ts,mts,cts}'],
     languageOptions: {
       globals: {
         ...globals.node,
@@ -120,9 +123,9 @@ export default [
   },
   {
     files: [
-      'test/es-module/**/*.{js,mjs}',
-      'test/parallel/**/*.{js,mjs}',
-      'test/sequential/**/*.{js,mjs}',
+      'test/es-module/**/*.{js,mjs,ts,mts,cts}',
+      'test/parallel/**/*.{js,mjs,ts,mts,cts}',
+      'test/sequential/**/*.{js,mjs,ts,mts,cts}',
     ],
     rules: {
       '@stylistic/js/comma-dangle': [
@@ -147,6 +150,15 @@ export default [
       'node-core/require-common-first': 'off',
     },
   },
+  {
+    files: [
+      'test/{common,wpt}/**/*.{ts,mts,cts}',
+    ],
+    rules: {
+      'node-core/required-modules': 'off',
+      'node-core/require-common-first': 'off',
+    },
+  },
   {
     files: [
       'test/es-module/test-esm-example-loader.js',

test/fixtures/source-map/output/source_map_throw_async_stack_trace.mts

@@ -4,8 +4,8 @@ import '../../../common/index.mjs';
 
 interface Foo {
   /** line
-   *
-   * blocks */
+  *
+  * blocks */
 }
 
 async function Throw() {

test/fixtures/source-map/output/source_map_throw_construct.mts

@@ -3,9 +3,9 @@
 import '../../../common/index.mjs';
 
 interface Block {
-  /** line
-   *
-   * blocks */
+  /* line
+  *
+  * blocks */
 }
 
 class Foo {

tools/eslint/eslint.config_partial.mjs

@@ -2,7 +2,7 @@ import { globals } from './eslint.config_utils.mjs';
 
 export default [
   {
-    files: ['tools/**/*.{js,mjs,cjs}'],
+    files: ['tools/**/*.{js,mjs,cjs,ts,mts,cts}'],
     languageOptions: {
       globals: {
         ...globals.node,