Migrate to ESLint 9 with flat config and fix monorepo linting

.changeset/changelog-github-custom.ts

@@ -12,13 +12,15 @@ const changelogFunctions: ChangelogFunctions = {
         'Please provide a repo to this changelog generator like this:\n"changelog": ["@changesets/changelog-github", { "repo": "org/repo" }]'
       );
     }
-    if (dependenciesUpdated.length === 0) return '';
+    if (dependenciesUpdated.length === 0) {
+      return '';
+    }
 
     const changesetLink = `- Updated dependencies [${(
       await Promise.all(
         changesets.map(async (cs) => {
           if (cs.commit) {
-            let { links } = await getInfo({
+            const { links } = await getInfo({
               repo: options.repo,
               commit: cs.commit,
             });
@@ -45,12 +47,14 @@ const changelogFunctions: ChangelogFunctions = {
 
     let prFromSummary: number | undefined;
     let commitFromSummary: string | undefined;
-    let usersFromSummary: string[] = [];
+    const usersFromSummary: string[] = [];
 
     const replacedChangelog = changeset.summary
       .replace(/^\s*(?:pr|pull|pull\s+request):\s*#?(\d+)/im, (_, pr) => {
-        let num = Number(pr);
-        if (!isNaN(num)) prFromSummary = num;
+        const num = Number(pr);
+        if (!isNaN(num)) {
+          prFromSummary = num;
+        }
         return '';
       })
       .replace(/^\s*commit:\s*([^\s]+)/im, (_, commit) => {
@@ -91,7 +95,7 @@ const changelogFunctions: ChangelogFunctions = {
       }
       const commitToFetchFrom = commitFromSummary || changeset.commit;
       if (commitToFetchFrom) {
-        let { links } = await getInfo({
+        const { links } = await getInfo({
           repo: options.repo,
           commit: commitToFetchFrom,
         });

.changeset/giant-carpets-brake.md

@@ -0,0 +1,7 @@
+---
+'create-qwik': patch
+'@builder.io/qwik-city': patch
+'@builder.io/qwik': patch
+---
+
+Fix linting errors which were previously being ignored across the monorepo.

.changeset/grumpy-ladybugs-wonder.md

@@ -0,0 +1,5 @@
+---
+'eslint-plugin-qwik': patch
+---
+
+Improve types and README documentation with clear configuration examples for ESLint 9+ (flat config). Added `globalIgnores` for more clarity and `tseslint.config` for better type inference inside the `parserOptions` option.

eslint.config.js

@@ -0,0 +1,112 @@
+import globals from 'globals';
+import js from '@eslint/js';
+import tseslint from 'typescript-eslint';
+import noOnlyTests from 'eslint-plugin-no-only-tests';
+import { globalIgnores } from 'eslint/config';
+// import { qwikEslint9Plugin } from 'eslint-plugin-qwik';
+
+const ignores = [
+  '**/.history',
+  '**/.vscode',
+  '**/dist',
+  '**/dist-dev',
+  '**/lib',
+  '**/node_modules',
+  '**/tsc-out',
+  '**/external',
+  '**/*.',
+  '**/*.log',
+  '**/etc',
+  '**/target',
+  '**/temp',
+  '**/tsdoc-metadata.json',
+  '**/.DS_Store',
+  '**/*.mp4',
+  'scripts',
+  '**/server/**/*.js',
+  '**/*.tsbuildinfo',
+  'packages/docs/api',
+  'packages/docs/public/repl/repl-sw.js*',
+  'packages/docs/src/routes/examples/apps',
+  'packages/docs/src/routes/playground/app',
+  'packages/docs/src/routes/tutorial',
+  'packages/qwik-labs/lib',
+  'packages/qwik-labs/lib-types',
+  'packages/qwik-labs/vite',
+  'packages/insights/drizzle.config.ts',
+  'packages/insights/panda.config.ts',
+  'starters/apps/base',
+  'starters/apps/library',
+  'starters/templates',
+  '**/vite.config.ts',
+  // packages with eslint.config.mjs
+  'packages/qwik-labs',
+  'packages/insights',
+  'starters',
+  // eslint.config.*
+  '**/eslint.config.mjs',
+  '**/eslint.config.js',
+];
+
+export default tseslint.config(
+  globalIgnores(ignores),
+  js.configs.recommended,
+  tseslint.configs.recommended,
+  // qwikEslint9Plugin.configs.recommended,
+  {
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+        ...globals.es2021,
+      },
+      parserOptions: {
+        // Needed when using the qwik plugin
+        // projectService: true,
+        // tsconfigRootDir: import.meta.dirname,
+      },
+    },
+  },
+  {
+    plugins: {
+      'no-only-tests': noOnlyTests,
+    },
+    rules: {
+      'no-only-tests/no-only-tests': 'error',
+    },
+    name: 'no-only-tests',
+  },
+  {
+    rules: {
+      '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/explicit-module-boundary-types': 'off',
+      '@typescript-eslint/no-inferrable-types': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'off',
+      '@typescript-eslint/no-empty-interface': 'off',
+      '@typescript-eslint/no-namespace': 'off',
+      '@typescript-eslint/no-empty-function': 'off',
+      '@typescript-eslint/no-this-alias': 'off',
+      '@typescript-eslint/ban-types': 'off',
+      '@typescript-eslint/ban-ts-comment': 'off',
+      'prefer-spread': 'off',
+      'no-case-declarations': 'off',
+      'no-console': ['error', { allow: ['warn', 'error'] }],
+      'no-only-tests/no-only-tests': 'error',
+      '@typescript-eslint/no-unused-vars': 'off',
+      '@typescript-eslint/no-var-requires': 'off',
+      curly: 'error',
+      'no-new-func': 'error',
+      '@typescript-eslint/no-empty-object-type': 'off',
+      '@typescript-eslint/no-unused-expressions': 'off',
+      '@typescript-eslint/no-unsafe-function-type': 'off',
+      '@typescript-eslint/no-require-imports': 'off',
+      '@typescript-eslint/no-wrapper-object-types': 'off',
+    },
+  },
+  {
+    files: ['packages/docs/**/*.{ts,tsx}'],
+    rules: {
+      'no-console': 'off',
+    },
+  }
+);

package.json

@@ -9,16 +9,6 @@
   "config": {
     "syncpack": {
       "versionGroups": [
-        {
-          "label": "Allow ESLint 9 types in eslint-plugin-qwik",
-          "dependencies": [
-            "@types/eslint"
-          ],
-          "packages": [
-            "eslint-plugin-qwik"
-          ],
-          "policy": "matches@9.6.1"
-        },
         {
           "label": "Be lenient in vite versions for prod. v4 is broken, v5 is good",
           "dependencyTypes": [
@@ -115,7 +105,7 @@
     "@changesets/get-github-info": "0.6.0",
     "@changesets/types": "6.0.0",
     "@clack/prompts": "0.7.0",
-    "@eslint/eslintrc": "3.1.0",
+    "@eslint/js": "9.22.0",
     "@mdx-js/mdx": "3.0.1",
     "@microsoft/api-documenter": "7.24.2",
     "@microsoft/api-extractor": "7.43.1",
@@ -127,7 +117,6 @@
     "@types/brotli": "1.3.4",
     "@types/bun": "1.1.6",
     "@types/cross-spawn": "6.0.6",
-    "@types/eslint": "8.56.10",
     "@types/express": "4.17.21",
     "@types/node": "20.14.11",
     "@types/path-browserify": "1.0.2",
@@ -136,8 +125,6 @@
     "@types/semver": "7.5.8",
     "@types/tmp": "0.2.6",
     "@types/which-pm-runs": "1.0.2",
-    "@typescript-eslint/eslint-plugin": "7.16.1",
-    "@typescript-eslint/parser": "7.16.1",
     "all-contributors-cli": "6.26.1",
     "brotli": "1.3.3",
     "concurrently": "8.2.2",
@@ -146,11 +133,12 @@
     "csstype": "3.1.3",
     "dotenv": "16.4.5",
     "esbuild": "0.20.2",
-    "eslint": "8.57.0",
-    "eslint-plugin-no-only-tests": "3.1.0",
+    "eslint": "9.22.0",
+    "eslint-plugin-no-only-tests": "3.3.0",
     "eslint-plugin-qwik": "workspace:^",
     "execa": "8.0.1",
     "express": "4.20.0",
+    "globals": "16.0.0",
     "install": "0.13.0",
     "memfs": "4.14.0",
     "monaco-editor": "0.45.0",
@@ -172,6 +160,7 @@
     "tree-kill": "1.2.2",
     "tsx": "4.19.1",
     "typescript": "5.4.5",
+    "typescript-eslint": "8.26.1",
     "undici": "*",
     "vfile": "6.0.2",
     "vite": "5.3.5",
@@ -237,8 +226,8 @@
     "link.dist.npm": "cd packages/qwik && npm link && cd ../qwik-city && npm link && cd ../eslint-plugin-qwik && npm link && cd ../qwik-react && npm link",
     "link.dist.yarn": "cd packages/qwik && yarn link && cd ../qwik-city && yarn link && cd ../eslint-plugin-qwik && yarn link && cd ../qwik-react && yarn link",
     "lint": "pnpm lint.eslint && pnpm lint.prettier && pnpm lint.rust",
-    "lint.eslint": "eslint --cache \"**/*.ts*\"",
-    "lint.fix": "eslint --fix \"**/*.ts*\" && pnpm prettier.fix",
+    "lint.eslint": "eslint --cache \"**/*.ts*\" && pnpm -r --parallel lint",
+    "lint.fix": "eslint --fix \"**/*.ts*\" && pnpm -r --parallel lint.fix && pnpm prettier.fix",
     "lint.prettier": "prettier --cache --check .",
     "lint.rust": "make lint",
     "lint.syncpack": "syncpack list-mismatches",

packages/create-qwik/index.ts

@@ -1,4 +1,3 @@
-/* eslint-disable no-console */
 import { runCreateCli } from './src/run-create-cli';
 import { runCreateInteractiveCli } from './src/run-create-interactive-cli';
 import { panic, printHeader } from '../qwik/src/cli/utils/utils';

packages/create-qwik/src/run-create-interactive-cli.ts

@@ -7,7 +7,7 @@ import { join, relative } from 'node:path';
 import type { CreateAppResult } from '../../qwik/src/cli/types';
 import { clearDir } from './helpers/clearDir';
 import { createApp } from './create-app';
-/* eslint-disable no-console */
+
 import fs from 'node:fs';
 import { getRandomJoke } from './helpers/jokes';
 import { installDepsCli } from './helpers/installDepsCli';

packages/docs/codesandbox.sync.ts

@@ -1,4 +1,3 @@
-/* eslint-disable no-console */
 import { readdirSync, readFileSync, writeFileSync } from 'node:fs';
 import { join } from 'node:path';
 

packages/docs/contributors.ts

@@ -1,4 +1,3 @@
-/* eslint-disable no-console */
 import { fetch } from 'undici';
 import fs from 'node:fs';
 import path from 'node:path';

packages/docs/package.json

@@ -21,6 +21,10 @@
     "@mui/system": "5.16.4",
     "@mui/x-data-grid": "6.20.4",
     "@qwik-ui/headless": "0.5.0",
+    "@shikijs/colorized-brackets": "3.1.0",
+    "@shikijs/rehype": "3.1.0",
+    "@shikijs/transformers": "3.1.0",
+    "@shikijs/types": "3.1.0",
     "@supabase/supabase-js": "2.44.4",
     "@types/leaflet": "1.9.12",
     "@types/prismjs": "1.26.4",
@@ -43,6 +47,7 @@
     "qwik-image": "0.0.10",
     "react": "18.3.1",
     "react-dom": "18.3.1",
+    "shiki": "3.1.0",
     "snarkdown": "2.0.0",
     "tailwindcss": "3.4.6",
     "terser": "5.31.3",
@@ -52,11 +57,6 @@
     "valibot": "0.33.3",
     "vite": "5.3.5",
     "vite-plugin-inspect": "0.8.5",
-    "shiki": "3.1.0",
-    "@shikijs/rehype": "3.1.0",
-    "@shikijs/transformers": "3.1.0",
-    "@shikijs/colorized-brackets": "3.1.0",
-    "@shikijs/types": "3.1.0",
     "wrangler": "3.65.1"
   },
   "engines": {

packages/docs/src/components/router-head/router-head.tsx

@@ -1,4 +1,3 @@
-/* eslint-disable no-console */
 import { component$ } from '@builder.io/qwik';
 import { useDocumentHead, useLocation } from '@builder.io/qwik-city';
 import { Social } from './social';

packages/docs/src/repl/repl-version.ts

@@ -1,4 +1,3 @@
-/* eslint-disable no-console */
 import { QWIK_PKG_NAME, bundled } from './bundled';
 
 const bundledVersion = bundled[QWIK_PKG_NAME].version;

packages/docs/src/repl/repl.tsx

@@ -1,4 +1,3 @@
-/* eslint-disable no-console */
 import {
   component$,
   noSerialize,