lint: migrate to ESLint v9

apps/docs/app/(home)/page.tsx

@@ -119,7 +119,6 @@ function Why(): React.ReactElement {
     >
       {new Array(10).fill(0).map((_, i) => (
         <div
-          // eslint-disable-next-line react/no-array-index-key -- static
           key={i}
           className="absolute -left-20 top-0 z-[-1] h-[1000px] max-h-[100vw] origin-top-right rotate-45 bg-gradient-to-b from-primary blur-xl"
           style={{

apps/docs/app/(home)/sponsors/page.tsx

@@ -127,7 +127,6 @@ export default async function Page(): Promise<ReactNode> {
           strokeWidth="0.5"
         />
         {new Array(3).fill(null).map((_, i) => (
-          // eslint-disable-next-line react/no-array-index-key -- safe
           <Fragment key={i}>
             <rect
               x="368"

apps/docs/components/ai/search-ai.tsx

@@ -78,7 +78,7 @@ let session: AnswerSession | undefined;
 export function AIDialog(): React.ReactElement {
   const [message, setMessage] = useState('');
   const [loading, setLoading] = useState(false);
-  // eslint-disable-next-line react/hook-use-state -- rerender
+
   const [_, update] = useState<unknown>();
   const shouldFocus = useRef(false); // should focus on input on next render
   const [relatedQueries, setRelatedQueries] = useState<string[]>([]);
@@ -166,7 +166,6 @@ export function AIDialog(): React.ReactElement {
     <>
       <List className={cn(messages.length === 0 && 'hidden')}>
         {messages.map((item, i) => (
-          // eslint-disable-next-line react/no-array-index-key -- safe
           <Message key={i} {...item}>
             {!loading &&
             item.role === 'assistant' &&

apps/docs/eslint.config.mjs

@@ -0,0 +1,22 @@
+import next from 'eslint-config-custom/next.js';
+
+export default [
+  {
+    ignores: [
+      'dist',
+      'node_modules',
+      '.next/',
+      'out/',
+      'next.config.mjs',
+      'postcss.config.js',
+    ],
+  },
+  ...next,
+  {
+    rules: {
+      'no-console': 'off',
+      // for Fumadocs CLI
+      'import/no-relative-packages': 'off',
+    },
+  },
+];

package.json

@@ -16,20 +16,21 @@
     "types:check": "turbo run types:check",
     "version": "changeset version && pnpm install --lockfile-only"
   },
-  "prettier": "@vercel/style-guide/prettier",
   "devDependencies": {
     "@changesets/cli": "^2.27.9",
-    "@typescript-eslint/eslint-plugin": "^8.9.0",
-    "@typescript-eslint/parser": "^8.9.0",
-    "@vercel/style-guide": "^6.0.0",
+    "@eslint/js": "^9.12.0",
+    "@types/eslint__js": "^8.42.3",
     "concurrently": "^9.0.1",
-    "eslint": "^8.57.1",
+    "eslint": "^9.12.0",
+    "eslint-plugin-react": "^7.37.1",
+    "eslint-plugin-react-hooks": "5.1.0-rc-bf7e210c-20241017",
     "eslint-plugin-tailwindcss": "^3.17.5",
     "prettier": "^3.3.3",
     "rimraf": "^6.0.1",
     "tsup": "8.3.0",
     "turbo": "2.1.3",
     "typescript": "^5.6.3",
+    "typescript-eslint": "^8.10.0",
     "vitest": "^2.1.3"
   },
   "packageManager": "[email protected]",

packages/cli/eslint.config.mjs

@@ -0,0 +1,13 @@
+import library from 'eslint-config-custom/library.js';
+
+export default [
+  {
+    ignores: ['dist', 'node_modules', 'test/repo', 'test/repo-2'],
+  },
+  ...library,
+  {
+    rules: {
+      'import/no-relative-packages': 'off',
+    },
+  },
+];

packages/cli/src/config.ts

@@ -38,7 +38,7 @@ export async function loadConfig(file = './cli.json'): Promise<Config> {
     const content = await fs.readFile(file);
 
     return JSON.parse(content.toString()) as Config;
-  } catch (_) {
+  } catch {
     return {};
   }
 }

packages/cli/src/index.ts

@@ -154,7 +154,7 @@ program
 
       try {
         nodes = JSON.parse(str ?? '') as JsonTreeNode[];
-      } catch (e) {
+      } catch {
         nodes = await runTree(str ?? './');
       }
 

packages/cli/src/utils/i18n/transform-layout-config.ts

@@ -9,7 +9,7 @@ export async function transformLayoutConfig(
 
   try {
     content = await fs.readFile(filePath).then((res) => res.toString());
-  } catch (_) {
+  } catch {
     return;
   }
 

packages/cli/src/utils/i18n/transform-root-layout.ts

@@ -11,7 +11,7 @@ export async function transformRootLayout(
 
   try {
     content = await fs.readFile(filePath).then((res) => res.toString());
-  } catch (_) {
+  } catch {
     return;
   }
 

packages/cli/src/utils/i18n/transform-source-i18n.ts

@@ -13,7 +13,7 @@ export async function transformSourceI18n(
 
   try {
     content = await fs.readFile(filePath).then((res) => res.toString());
-  } catch (e) {
+  } catch {
     return;
   }
   const sourceFile = project.createSourceFile(filePath, content, {

packages/cli/src/utils/move-files.ts

@@ -1,6 +1,5 @@
 import fs from 'node:fs/promises';
 import path from 'node:path';
-import { type Stats } from 'node:fs';
 import { type Project } from 'ts-morph';
 import { isRelative } from '@/utils/fs';
 import {
@@ -26,13 +25,8 @@ export async function moveFiles(
    */
   originalDir = from,
 ): Promise<void> {
-  let stats: Stats;
-
-  try {
-    stats = await fs.lstat(from);
-  } catch (_) {
-    return;
-  }
+  const stats = await fs.lstat(from).catch(() => undefined);
+  if (!stats) return;
 
   if (stats.isDirectory()) {
     const items = await fs.readdir(from);
@@ -50,11 +44,9 @@ export async function moveFiles(
       }),
     );
 
-    try {
-      await fs.rmdir(from);
-    } catch (_) {
+    await fs.rmdir(from).catch(() => {
       // it is possible that some files are ignored, so the directory isn't empty
-    }
+    });
   }
 
   if (!stats.isFile()) return;

packages/content-collections/eslint.config.mjs

@@ -0,0 +1,8 @@
+import library from 'eslint-config-custom/library.js';
+
+export default [
+  {
+    ignores: ['dist', 'node_modules', '*.test.ts'],
+  },
+  ...library,
+];

packages/content-collections/src/configuration.ts

@@ -141,7 +141,6 @@ export async function transformMDX<D extends BaseDoc>(
   );
 }
 
-// eslint-disable-next-line @typescript-eslint/explicit-function-return-type -- The type is dynamically generated by Zod
 export function createDocSchema(z: typeof Zod) {
   return {
     title: z.string(),
@@ -153,7 +152,6 @@ export function createDocSchema(z: typeof Zod) {
   };
 }
 
-// eslint-disable-next-line @typescript-eslint/explicit-function-return-type -- The type is dynamically generated by Zod
 export function createMetaSchema(z: typeof Zod) {
   return {
     title: z.string().optional(),

packages/core/eslint.config.mjs

@@ -0,0 +1,15 @@
+import next from 'eslint-config-custom/next.js';
+
+export default [
+  {
+    ignores: ['dist/', 'node_modules/', '*.test.ts', '*.output.js'],
+  },
+  ...next,
+  {
+    rules: {
+      'no-console': 'off',
+      // handled by bundler
+      'import/no-cycle': 'off',
+    },
+  },
+];

packages/core/src/utils/remove-undefined.ts

@@ -1,7 +1,6 @@
 export function removeUndefined<T extends object>(value: T): T {
   const obj = value as Record<string, unknown>;
   Object.keys(obj).forEach((key) => {
-    // eslint-disable-next-line @typescript-eslint/no-dynamic-delete -- Remove undefined values
     if (obj[key] === undefined) delete obj[key];
   });
 

packages/core/test/loader.test.ts

@@ -8,6 +8,7 @@ import {
 } from '@/source/loader';
 import { parseFilePath } from '@/source';
 import { PageTree } from '../dist/server';
+import type { ReactElement } from 'react';
 
 test('get slugs', () => {
   expect(getSlugs(parseFilePath('index.mdx'))).toStrictEqual([]);
@@ -90,7 +91,7 @@ test('Loader: Simple', () => {
 
 test('Nested Directories', async () => {
   const result = loader({
-    icon: (v) => v as any,
+    icon: (v) => v as unknown as ReactElement,
     pageTree: {
       noRef: true,
     },

packages/core/test/mdx-plugins.test.ts

@@ -12,7 +12,6 @@ import {
 import { fileURLToPath } from 'node:url';
 import remarkMdx from 'remark-mdx';
 import remarkGfm from 'remark-gfm';
-import remarkRehype from 'remark-rehype';
 import { createProcessor } from '@mdx-js/mdx';
 
 const cwd = path.dirname(fileURLToPath(import.meta.url));

packages/create-app/eslint.config.mjs

@@ -0,0 +1,13 @@
+import library from 'eslint-config-custom/next.js';
+
+export default [
+  {
+    ignores: ['dist/', 'scripts/', 'node_modules/', 'template/'],
+  },
+  ...library,
+  {
+    rules: {
+      'import/no-relative-packages': 'off',
+    },
+  },
+];

packages/create-app/src/git.ts

@@ -12,7 +12,7 @@ function isInGitRepository(cwd: string): boolean {
   try {
     execSync('git rev-parse --is-inside-work-tree', { stdio: 'ignore', cwd });
     return true;
-  } catch (_) {
+  } catch {
     return false;
   }
 }
@@ -21,7 +21,7 @@ function isInMercurialRepository(cwd: string): boolean {
   try {
     execSync('hg --cwd . root', { stdio: 'ignore', cwd });
     return true;
-  } catch (_) {
+  } catch {
     return false;
   }
 }
@@ -30,7 +30,7 @@ function isDefaultBranchSet(cwd: string): boolean {
   try {
     execSync('git config init.defaultBranch', { stdio: 'ignore', cwd });
     return true;
-  } catch (_) {
+  } catch {
     return false;
   }
 }
@@ -57,11 +57,11 @@ export function tryGitInit(root: string): boolean {
       cwd: root,
     });
     return true;
-  } catch (e) {
+  } catch {
     if (didInit) {
       try {
         rmSync(join(root, '.git'), { recursive: true, force: true });
-      } catch (_) {
+      } catch {
         // do nothing
       }
     }

packages/doc-gen/eslint.config.mjs

@@ -0,0 +1,8 @@
+import library from 'eslint-config-custom/library.js';
+
+export default [
+  ...library,
+  {
+    ignores: ['dist/', 'node_modules/', '*.test.ts', '**/test/fixtures/'],
+  },
+];