chore: release v0.39.3

Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>

.npmrc

@@ -1 +1,2 @@
 strict-peer-dependencies=false
+shamefully-hoist=true

README.md

@@ -3,7 +3,7 @@
 [![npm](https://img.shields.io/npm/v/@antfu/eslint-config?color=a1b858&label=)](https://npmjs.com/package/@antfu/eslint-config)
 
 - Single quotes, no semi
-- Auto fix for formatting (aimed to be used standalone without Prettier)
+- Auto fix for formatting (aimed to be used standalone **without** Prettier)
 - Designed to work with TypeScript, Vue out-of-box
 - Lint also for json, yaml, markdown
 - Sorted imports, dangling commas
@@ -68,9 +68,53 @@ module.exports = {
 }
 ```
 
-## Extended Reading
+### Lint Staged
 
-Learn more about the context - [Why I don't use Prettier](https://antfu.me/posts/why-not-prettier).
+If you want to apply lint and auto-fix before every commit, you can add the following to your `package.json`:
+
+```json
+{
+  "simple-git-hooks": {
+    "pre-commit": "pnpm lint-staged"
+  },
+  "lint-staged": {
+    "*": "eslint --fix"
+  }
+}
+```
+
+and then
+
+```bash
+npm i -D lint-staged simple-git-hooks
+```
+
+## FAQ
+
+### Prettier?
+
+[Why I don't use Prettier](https://antfu.me/posts/why-not-prettier)
+
+### How to lint CSS?
+
+This config does NOT lint CSS. I personally use [UnoCSS](https://github.com/unocss/unocss) so I don't write CSS. If you still prefer CSS, you can use [stylelint](https://stylelint.io/) for CSS linting.
+
+### I prefer XXX...
+
+Sure, you can override the rules in your `.eslintrc` file.
+
+<!-- eslint-skip -->
+
+```jsonc
+{
+  "extends": "@antfu",
+  "rules": {
+    // your rules...
+  }
+}
+```
+
+Or you can always fork this repo and make your own.
 
 ## Check Also
 

fixtures/vitesse/package.json

@@ -1,7 +1,7 @@
 {
   "type": "module",
   "private": true,
-  "packageManager": "pnpm@7.29.3",
+  "packageManager": "pnpm@8.5.1",
   "scripts": {
     "build": "vite-ssg build",
     "dev": "vite --port 3333 --open",
@@ -15,48 +15,48 @@
     "up": "taze major -I"
   },
   "dependencies": {
-    "@unocss/reset": "^0.50.6",
-    "@vueuse/core": "^9.13.0",
-    "@vueuse/head": "^1.1.23",
+    "@unocss/reset": "^0.52.1",
+    "@vueuse/core": "^10.1.2",
+    "@vueuse/head": "^1.1.26",
     "nprogress": "^0.2.0",
-    "pinia": "^2.0.33",
-    "vue": "^3.2.47",
-    "vue-demi": "^0.13.11",
+    "pinia": "^2.1.3",
+    "vue": "^3.3.4",
+    "vue-demi": "^0.14.5",
     "vue-i18n": "^9.2.2",
-    "vue-router": "^4.1.6"
+    "vue-router": "^4.2.1"
   },
   "devDependencies": {
-    "@antfu/eslint-config": "^0.36.0",
+    "@antfu/eslint-config": "^0.39.1",
     "@iconify-json/carbon": "^1.1.16",
     "@intlify/vite-plugin-vue-i18n": "^7.0.0",
     "@types/markdown-it-link-attributes": "^3.0.1",
     "@types/nprogress": "^0.2.0",
-    "@vitejs/plugin-vue": "^4.1.0",
-    "@vue/test-utils": "^2.3.1",
+    "@vitejs/plugin-vue": "^4.2.3",
+    "@vue/test-utils": "^2.3.2",
     "critters": "^0.0.16",
     "cross-env": "^7.0.3",
-    "cypress": "^12.8.1",
-    "eslint": "^8.36.0",
-    "eslint-plugin-cypress": "^2.12.1",
+    "cypress": "^12.12.0",
+    "eslint": "^8.41.0",
+    "eslint-plugin-cypress": "^2.13.3",
     "https-localhost": "^4.7.1",
     "markdown-it-link-attributes": "^4.0.1",
-    "markdown-it-shiki": "^0.8.0",
-    "pnpm": "^7.29.3",
-    "shiki": "^0.14.1",
-    "taze": "^0.9.0",
-    "typescript": "^5.0.2",
-    "unocss": "^0.50.6",
-    "unplugin-auto-import": "^0.15.1",
+    "markdown-it-shiki": "^0.9.0",
+    "pnpm": "^8.5.1",
+    "shiki": "^0.14.2",
+    "taze": "^0.10.1",
+    "typescript": "^5.0.4",
+    "unocss": "^0.52.1",
+    "unplugin-auto-import": "^0.16.2",
     "unplugin-vue-components": "^0.24.1",
-    "vite": "^4.2.0",
-    "vite-plugin-inspect": "^0.7.17",
-    "vite-plugin-pages": "^0.29.0",
-    "vite-plugin-pwa": "^0.14.4",
+    "vite": "^4.3.8",
+    "vite-plugin-inspect": "^0.7.26",
+    "vite-plugin-pages": "^0.30.1",
+    "vite-plugin-pwa": "^0.15.0",
     "vite-plugin-vue-layouts": "^0.8.0",
-    "vite-plugin-vue-markdown": "^0.22.4",
-    "vite-ssg": "^0.22.1",
-    "vite-ssg-sitemap": "^0.4.3",
-    "vitest": "^0.29.3",
-    "vue-tsc": "^1.2.0"
+    "vite-plugin-vue-markdown": "^0.23.5",
+    "vite-ssg": "^0.22.2",
+    "vite-ssg-sitemap": "^0.5.1",
+    "vitest": "^0.31.1",
+    "vue-tsc": "^1.6.5"
   }
 }

fixtures/vitesse/src/components/Footer.vue

@@ -1,7 +1,7 @@
 <script setup lang="ts">
 const { t, availableLocales, locale } = useI18n()
 
-const toggleLocales = () => {
+function toggleLocales() {
   // change to some real logic
   const locales = availableLocales
   locale.value = locales[(locales.indexOf(locale.value) + 1) % locales.length]

fixtures/vitesse/src/pages/index.vue

@@ -3,7 +3,7 @@ const user = useUserStore()
 const name = $ref(user.savedName)
 
 const router = useRouter()
-const go = () => {
+function go() {
   if (name)
     router.push(`/hi/${encodeURIComponent(name)}`)
 }

package.json

@@ -1,22 +1,23 @@
 {
   "name": "@antfu/eslint-config-monorepo",
-  "version": "0.37.0",
+  "version": "0.39.3",
   "private": true,
-  "packageManager": "pnpm@7.29.3",
+  "packageManager": "pnpm@8.5.1",
   "author": "Anthony Fu <anthonyfu117@hotmail.com> (https://github.com/antfu/)",
   "license": "MIT",
   "scripts": {
-    "lint": "eslint .",
+    "lint": "pnpm -r run stub && eslint .",
     "test": "pnpm -r run test",
+    "build": "pnpm -r run build",
     "prepare": "pnpm -r run stub",
     "release": "bumpp -r && pnpm -r publish"
   },
   "devDependencies": {
-    "@antfu/eslint-config": "*",
-    "bumpp": "^9.0.0",
-    "eslint": "^8.36.0",
-    "eslint-plugin-antfu": "workspace:*",
-    "rimraf": "^4.4.0",
-    "typescript": "^5.0.2"
+    "@antfu/eslint-config": "workspace:*",
+    "bumpp": "^9.1.0",
+    "eslint": "^8.41.0",
+    "eslint-plugin-antfu": "link:./packages/eslint-plugin-antfu",
+    "rimraf": "^5.0.1",
+    "typescript": "^5.0.4"
   }
 }

packages/eslint-config-basic/index.js

@@ -42,6 +42,8 @@ module.exports = {
     '!.github',
     '!.vitepress',
     '!.vscode',
+    // force exclude
+    '.vitepress/cache',
   ],
   plugins: [
     'html',
@@ -57,7 +59,7 @@ module.exports = {
   },
   overrides: [
     {
-      files: ['*.json', '*.json5'],
+      files: ['*.json', '*.json5', '*.jsonc'],
       parser: 'jsonc-eslint-parser',
       rules: {
         'jsonc/array-bracket-spacing': ['error', 'never'],
@@ -154,9 +156,10 @@ module.exports = {
       },
     },
     {
-      files: ['*.js', '*.cjs'],
+      files: ['*.js', '*.cjs', '*.jsx'],
       rules: {
         '@typescript-eslint/no-var-requires': 'off',
+        '@typescript-eslint/no-require-imports': 'off',
       },
     },
     {
@@ -188,6 +191,8 @@ module.exports = {
         '@typescript-eslint/no-var-requires': 'off',
         '@typescript-eslint/comma-dangle': 'off',
         '@typescript-eslint/consistent-type-imports': 'off',
+        '@typescript-eslint/no-namespace': 'off',
+        '@typescript-eslint/no-require-imports': 'off',
         'import/no-unresolved': 'off',
         'unused-imports/no-unused-imports': 'off',
         'unused-imports/no-unused-vars': 'off',
@@ -197,6 +202,8 @@ module.exports = {
         'no-undef': 'off',
         'no-unused-expressions': 'off',
         'no-unused-vars': 'off',
+        'antfu/no-cjs-exports': 'off',
+        'antfu/no-ts-export-equal': 'off',
       },
     },
   ],
@@ -207,6 +214,7 @@ module.exports = {
     'import/no-mutable-exports': 'error',
     'import/no-unresolved': 'off',
     'import/no-absolute-path': 'off',
+    'import/newline-after-import': ['error', { count: 1, considerComments: true }],
 
     // Common
     'semi': ['error', 'never'],
@@ -308,12 +316,18 @@ module.exports = {
     'no-with': 'error',
     'no-void': 'error',
     'no-useless-escape': 'off',
+    'no-invalid-this': 'error',
     'vars-on-top': 'error',
     'require-await': 'off',
     'no-return-assign': 'off',
     'operator-linebreak': ['error', 'before'],
     'max-statements-per-line': ['error', { max: 1 }],
 
+    // node
+    // 'n/prefer-global/process': ['error', 'never'], // Not sure if we need it as we are using `process.env.NODE_ENV` a lot in front-end.
+    'n/prefer-global/buffer': ['error', 'never'],
+    'n/no-callback-literal': 'off',
+
     // unicorns
     // Pass error message when throwing errors
     'unicorn/error-message': 'error',
@@ -345,7 +359,6 @@ module.exports = {
     'import/no-named-as-default-member': 'off',
     'import/no-named-as-default': 'off',
     'import/namespace': 'off',
-    'n/no-callback-literal': 'off',
 
     'sort-imports': [
       'error',
@@ -365,6 +378,7 @@ module.exports = {
     // antfu
     'antfu/if-newline': 'error',
     'antfu/import-dedupe': 'error',
+    'antfu/top-level-function': 'error',
     // 'antfu/prefer-inline-type-import': 'error',
   },
 }

packages/eslint-config-basic/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antfu/eslint-config-basic",
-  "version": "0.37.0",
+  "version": "0.39.3",
   "description": "",
   "author": "Anthony Fu <anthonyfu117@hotmail.com> (https://github.com/antfu/)",
   "license": "MIT",
@@ -23,18 +23,18 @@
     "eslint-plugin-eslint-comments": "^3.2.0",
     "eslint-plugin-html": "^7.1.0",
     "eslint-plugin-import": "^2.27.5",
-    "eslint-plugin-jsonc": "^2.7.0",
+    "eslint-plugin-jsonc": "^2.8.0",
     "eslint-plugin-markdown": "^3.0.0",
-    "eslint-plugin-n": "^15.6.1",
+    "eslint-plugin-n": "^16.0.0",
     "eslint-plugin-no-only-tests": "^3.1.0",
     "eslint-plugin-promise": "^6.1.1",
-    "eslint-plugin-unicorn": "^46.0.0",
+    "eslint-plugin-unicorn": "^47.0.0",
     "eslint-plugin-unused-imports": "^2.0.0",
-    "eslint-plugin-yml": "^1.5.0",
-    "jsonc-eslint-parser": "^2.2.0",
-    "yaml-eslint-parser": "^1.2.0"
+    "eslint-plugin-yml": "^1.7.0",
+    "jsonc-eslint-parser": "^2.3.0",
+    "yaml-eslint-parser": "^1.2.2"
   },
   "devDependencies": {
-    "eslint": "^8.36.0"
+    "eslint": "^8.41.0"
   }
 }

packages/eslint-config-react/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antfu/eslint-config-react",
-  "version": "0.37.0",
+  "version": "0.39.3",
   "description": "",
   "author": "Anthony Fu <anthonyfu117@hotmail.com> (https://github.com/antfu/)",
   "license": "MIT",
@@ -24,8 +24,8 @@
     "eslint-plugin-react-hooks": "^4.6.0"
   },
   "devDependencies": {
-    "eslint": "^8.36.0",
+    "eslint": "^8.41.0",
     "react": "^18.2.0",
-    "typescript": "^5.0.2"
+    "typescript": "^5.0.4"
   }
 }

packages/eslint-config-ts/index.js

@@ -71,6 +71,7 @@ module.exports = {
     '@typescript-eslint/consistent-type-imports': ['error', { prefer: 'type-imports', disallowTypeAnnotations: false }],
     '@typescript-eslint/consistent-type-definitions': ['error', 'interface'],
     '@typescript-eslint/prefer-ts-expect-error': 'error',
+    '@typescript-eslint/no-require-imports': 'error',
 
     // Override JS
     'no-useless-constructor': 'off',
@@ -113,6 +114,8 @@ module.exports = {
       ],
       offsetTernaryExpressions: true,
     }],
+    'no-invalid-this': 'off',
+    '@typescript-eslint/no-invalid-this': 'error',
     'no-redeclare': 'off',
     '@typescript-eslint/no-redeclare': 'error',
     'no-use-before-define': 'off',
@@ -155,6 +158,8 @@ module.exports = {
 
     // antfu
     'antfu/generic-spacing': 'error',
+    'antfu/no-cjs-exports': 'error',
+    'antfu/no-ts-export-equal': 'error',
 
     // off
     '@typescript-eslint/consistent-indexed-object-style': 'off',
@@ -169,7 +174,6 @@ module.exports = {
     '@typescript-eslint/no-non-null-assertion': 'off',
     '@typescript-eslint/explicit-module-boundary-types': 'off',
     '@typescript-eslint/ban-types': 'off',
-    '@typescript-eslint/no-namespace': 'off',
     '@typescript-eslint/triple-slash-reference': 'off',
     // handled by unused-imports/no-unused-imports
     '@typescript-eslint/no-unused-vars': 'off',

packages/eslint-config-ts/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antfu/eslint-config-ts",
-  "version": "0.37.0",
+  "version": "0.39.3",
   "description": "",
   "author": "Anthony Fu <anthonyfu117@hotmail.com> (https://github.com/antfu/)",
   "license": "MIT",
@@ -18,11 +18,11 @@
   },
   "dependencies": {
     "@antfu/eslint-config-basic": "workspace:*",
-    "@typescript-eslint/eslint-plugin": "^5.55.0",
-    "@typescript-eslint/parser": "^5.55.0",
+    "@typescript-eslint/eslint-plugin": "^5.59.7",
+    "@typescript-eslint/parser": "^5.59.7",
     "eslint-plugin-jest": "^27.2.1"
   },
   "devDependencies": {
-    "eslint": "^8.36.0"
+    "eslint": "^8.41.0"
   }
 }

packages/eslint-config-vue/index.js

@@ -36,6 +36,7 @@ module.exports = {
     'vue/multi-word-component-names': 'off',
     'vue/prefer-import-from-vue': 'off',
     'vue/no-v-text-v-html-on-component': 'off',
+    'vue/no-dupe-keys': 'off',
 
     // reactivity transform
     'vue/no-setup-props-destructure': 'off',

packages/eslint-config-vue/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antfu/eslint-config-vue",
-  "version": "0.37.0",
+  "version": "0.39.3",
   "description": "",
   "author": "Anthony Fu <anthonyfu117@hotmail.com> (https://github.com/antfu/)",
   "license": "MIT",
@@ -17,10 +17,10 @@
   "dependencies": {
     "@antfu/eslint-config-basic": "workspace:*",
     "@antfu/eslint-config-ts": "workspace:*",
-    "eslint-plugin-vue": "^9.9.0",
+    "eslint-plugin-vue": "^9.14.0",
     "local-pkg": "^0.4.3"
   },
   "devDependencies": {
-    "eslint": "^8.36.0"
+    "eslint": "^8.41.0"
   }
 }

packages/eslint-config/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antfu/eslint-config",
-  "version": "0.37.0",
+  "version": "0.39.3",
   "description": "Anthony's ESLint config",
   "author": "Anthony Fu <anthonyfu117@hotmail.com> (https://github.com/antfu/)",
   "license": "MIT",
@@ -17,21 +17,21 @@
   },
   "dependencies": {
     "@antfu/eslint-config-vue": "workspace:*",
-    "@typescript-eslint/eslint-plugin": "^5.55.0",
-    "@typescript-eslint/parser": "^5.55.0",
+    "@typescript-eslint/eslint-plugin": "^5.59.7",
+    "@typescript-eslint/parser": "^5.59.7",
     "eslint-plugin-eslint-comments": "^3.2.0",
     "eslint-plugin-html": "^7.1.0",
     "eslint-plugin-import": "^2.27.5",
-    "eslint-plugin-jsonc": "^2.7.0",
-    "eslint-plugin-n": "^15.6.1",
+    "eslint-plugin-jsonc": "^2.8.0",
+    "eslint-plugin-n": "^16.0.0",
     "eslint-plugin-promise": "^6.1.1",
-    "eslint-plugin-unicorn": "^46.0.0",
-    "eslint-plugin-vue": "^9.9.0",
-    "eslint-plugin-yml": "^1.5.0",
-    "jsonc-eslint-parser": "^2.2.0",
-    "yaml-eslint-parser": "^1.2.0"
+    "eslint-plugin-unicorn": "^47.0.0",
+    "eslint-plugin-vue": "^9.14.0",
+    "eslint-plugin-yml": "^1.7.0",
+    "jsonc-eslint-parser": "^2.3.0",
+    "yaml-eslint-parser": "^1.2.2"
   },
   "devDependencies": {
-    "eslint": "^8.36.0"
+    "eslint": "^8.41.0"
   }
 }

packages/eslint-plugin-antfu/package.json

@@ -1,6 +1,6 @@
 {
   "name": "eslint-plugin-antfu",
-  "version": "0.37.0",
+  "version": "0.39.3",
   "license": "MIT",
   "homepage": "https://github.com/antfu/eslint-config",
   "main": "./dist/index.cjs",
@@ -16,11 +16,11 @@
     "prepublishOnly": "nr build"
   },
   "dependencies": {
-    "@typescript-eslint/utils": "^5.55.0"
+    "@typescript-eslint/utils": "^5.59.7"
   },
   "devDependencies": {
-    "@types/node": "^18.15.3",
-    "unbuild": "^1.1.2",
-    "vitest": "^0.29.3"
+    "@types/node": "^20.2.3",
+    "unbuild": "^1.2.1",
+    "vitest": "^0.31.1"
   }
 }

packages/eslint-plugin-antfu/src/index.ts

@@ -2,6 +2,9 @@ import genericSpacing from './rules/generic-spacing'
 import ifNewline from './rules/if-newline'
 import importDedupe from './rules/import-dedupe'
 import preferInlineTypeImport from './rules/prefer-inline-type-import'
+import topLevelFunction from './rules/top-level-function'
+import noTsExportEqual from './rules/no-ts-export-equal'
+import noCjsExports from './rules/no-cjs-exports'
 
 export default {
   rules: {
@@ -9,5 +12,8 @@ export default {
     'import-dedupe': importDedupe,
     'prefer-inline-type-import': preferInlineTypeImport,
     'generic-spacing': genericSpacing,
+    'top-level-function': topLevelFunction,
+    'no-cjs-exports': noCjsExports,
+    'no-ts-export-equal': noTsExportEqual,
   },
 }

packages/eslint-plugin-antfu/src/rules/no-cjs-exports.test.ts

@@ -0,0 +1,28 @@
+import { RuleTester } from '@typescript-eslint/utils/dist/ts-eslint'
+import { it } from 'vitest'
+import rule, { RULE_NAME } from './no-cjs-exports'
+
+const valids = [
+  { code: 'export = {}', filename: 'test.ts' },
+  { code: 'exports.a = {}', filename: 'test.js' },
+  { code: 'module.exports.a = {}', filename: 'test.js' },
+]
+
+const invalids = [
+  { code: 'exports.a = {}', filename: 'test.ts' },
+  { code: 'module.exports.a = {}', filename: 'test.ts' },
+]
+
+it('runs', () => {
+  const ruleTester: RuleTester = new RuleTester({
+    parser: require.resolve('@typescript-eslint/parser'),
+  })
+
+  ruleTester.run(RULE_NAME, rule, {
+    valid: valids,
+    invalid: invalids.map(i => ({
+      ...i,
+      errors: [{ messageId: 'noCjsExports' }],
+    })),
+  })
+})

packages/eslint-plugin-antfu/src/rules/no-cjs-exports.ts

@@ -0,0 +1,41 @@
+import { createEslintRule } from '../utils'
+
+export const RULE_NAME = 'no-cjs-exports'
+export type MessageIds = 'noCjsExports'
+export type Options = []
+
+export default createEslintRule<Options, MessageIds>({
+  name: RULE_NAME,
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'Do not use CJS exports',
+      recommended: false,
+    },
+    schema: [],
+    messages: {
+      noCjsExports: 'Use ESM export instead',
+    },
+  },
+  defaultOptions: [],
+  create: (context) => {
+    const extension = context.getFilename().split('.').pop()
+    if (!['ts', 'tsx', 'mts', 'cts'].includes(extension))
+      return {}
+
+    return {
+      'MemberExpression[object.name="exports"]': function (node) {
+        context.report({
+          node,
+          messageId: 'noCjsExports',
+        })
+      },
+      'MemberExpression[object.name="module"][property.name="exports"]': function (node) {
+        context.report({
+          node,
+          messageId: 'noCjsExports',
+        })
+      },
+    }
+  },
+})

packages/eslint-plugin-antfu/src/rules/no-ts-export-equal.test.ts

@@ -0,0 +1,26 @@
+import { RuleTester } from '@typescript-eslint/utils/dist/ts-eslint'
+import { it } from 'vitest'
+import rule, { RULE_NAME } from './no-ts-export-equal'
+
+const valids = [
+  { code: 'export default {}', filename: 'test.ts' },
+  { code: 'export = {}', filename: 'test.js' },
+]
+
+const invalids = [
+  { code: 'export = {}', filename: 'test.ts' },
+]
+
+it('runs', () => {
+  const ruleTester: RuleTester = new RuleTester({
+    parser: require.resolve('@typescript-eslint/parser'),
+  })
+
+  ruleTester.run(RULE_NAME, rule, {
+    valid: valids,
+    invalid: invalids.map(i => ({
+      ...i,
+      errors: [{ messageId: 'noTsExportEqual' }],
+    })),
+  })
+})

packages/eslint-plugin-antfu/src/rules/no-ts-export-equal.ts

@@ -0,0 +1,35 @@
+import { createEslintRule } from '../utils'
+
+export const RULE_NAME = 'no-ts-export-equal'
+export type MessageIds = 'noTsExportEqual'
+export type Options = []
+
+export default createEslintRule<Options, MessageIds>({
+  name: RULE_NAME,
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'Do not use `exports =`',
+      recommended: false,
+    },
+    schema: [],
+    messages: {
+      noTsExportEqual: 'Use ESM `export default` instead',
+    },
+  },
+  defaultOptions: [],
+  create: (context) => {
+    const extension = context.getFilename().split('.').pop()
+    if (!['ts', 'tsx', 'mts', 'cts'].includes(extension))
+      return {}
+
+    return {
+      TSExportAssignment(node) {
+        context.report({
+          node,
+          messageId: 'noTsExportEqual',
+        })
+      },
+    }
+  },
+})

packages/eslint-plugin-antfu/src/rules/top-level-function.test.ts

@@ -0,0 +1,67 @@
+import { RuleTester } from '@typescript-eslint/utils/dist/ts-eslint'
+import { it } from 'vitest'
+import rule, { RULE_NAME } from './top-level-function'
+
+const valids = [
+  'function foo() {}',
+  // allow arrow function inside function
+  'function foo() { const bar = () => {} }',
+  // allow arrow function when type is specified
+  'const Foo: Bar = () => {}',
+  // allow let/var
+  'let foo = () => {}',
+  // allow arrow function in as
+  'const foo = (() => {}) as any',
+  // allow iife
+  ';(() => {})()',
+  // allow export default
+  'export default () => {}',
+  'export default defineConfig(() => {})',
+  // allow one-line arrow function
+  'const foo = (x, y) => x + y',
+  'const foo = async (x, y) => x + y',
+  'const foo = () => String(123)',
+  'const foo = () => ({})',
+]
+
+const invalids = [
+  [
+    'const foo = (x, y) => \nx + y',
+    'function foo (x, y) {\n  return x + y\n}',
+  ],
+  [
+    'const foo = (as: string, bar: number) => { return as + bar }',
+    'function foo (as: string, bar: number) { return as + bar }',
+  ],
+  [
+    'const foo = <K, T extends Boolean>(as: string, bar: number): Omit<T, K> => \nas + bar',
+    'function foo <K, T extends Boolean>(as: string, bar: number): Omit<T, K> {\n  return as + bar\n}',
+  ],
+  [
+    'export const foo = () => {}',
+    'export function foo () {}',
+  ],
+  [
+    'export const foo = () => \n({})',
+    'export function foo () {\n  return {}\n}',
+  ],
+  [
+    'export const foo = async () => \n({})',
+    'export async function foo () {\n  return {}\n}',
+  ],
+]
+
+it('runs', () => {
+  const ruleTester: RuleTester = new RuleTester({
+    parser: require.resolve('@typescript-eslint/parser'),
+  })
+
+  ruleTester.run(RULE_NAME, rule, {
+    valid: valids,
+    invalid: invalids.map(i => ({
+      code: i[0],
+      output: i[1],
+      errors: [{ messageId: 'topLevelFunctionDeclaration' }],
+    })),
+  })
+})

packages/eslint-plugin-antfu/src/rules/top-level-function.ts

@@ -0,0 +1,88 @@
+import { createEslintRule } from '../utils'
+
+export const RULE_NAME = 'top-level-function'
+export type MessageIds = 'topLevelFunctionDeclaration'
+export type Options = []
+
+export default createEslintRule<Options, MessageIds>({
+  name: RULE_NAME,
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'Enforce top-level functions to be declared with function keyword',
+      recommended: 'error',
+    },
+    fixable: 'code',
+    schema: [],
+    messages: {
+      topLevelFunctionDeclaration: 'Top-level functions should be declared with function keyword',
+    },
+  },
+  defaultOptions: [],
+  create: (context) => {
+    return {
+      VariableDeclaration(node) {
+        if (node.parent.type !== 'Program' && node.parent.type !== 'ExportNamedDeclaration')
+          return
+
+        if (node.declarations.length !== 1)
+          return
+        if (node.kind !== 'const')
+          return
+        if (node.declare)
+          return
+
+        const declaration = node.declarations[0]
+
+        if (declaration.init?.type !== 'ArrowFunctionExpression')
+          return
+        if (declaration.id?.type !== 'Identifier')
+          return
+        if (declaration.id.typeAnnotation)
+          return
+        if (
+          declaration.init.body.type !== 'BlockStatement'
+          && declaration.id?.loc.start.line === declaration.init?.body.loc.end.line
+        )
+          return
+
+        const arrowFn = declaration.init
+        const body = declaration.init.body
+        const id = declaration.id
+
+        context.report({
+          node,
+          loc: {
+            start: id.loc.start,
+            end: body.loc.start,
+          },
+          messageId: 'topLevelFunctionDeclaration',
+          fix(fixer) {
+            const code = context.getSourceCode().text
+            const textName = code.slice(id.range[0], id.range[1])
+            const textArgs = arrowFn.params.length
+              ? code.slice(arrowFn.params[0].range[0], arrowFn.params[arrowFn.params.length - 1].range[1])
+              : ''
+            const textBody = body.type === 'BlockStatement'
+              ? code.slice(body.range[0], body.range[1])
+              : `{\n  return ${code.slice(body.range[0], body.range[1])}\n}`
+            const textGeneric = arrowFn.typeParameters
+              ? code.slice(arrowFn.typeParameters.range[0], arrowFn.typeParameters.range[1])
+              : ''
+            const textTypeReturn = arrowFn.returnType
+              ? code.slice(arrowFn.returnType.range[0], arrowFn.returnType.range[1])
+              : ''
+            const textAsync = arrowFn.async ? 'async ' : ''
+
+            const final = `${textAsync}function ${textName} ${textGeneric}(${textArgs})${textTypeReturn} ${textBody}`
+            // console.log({
+            //   input: code.slice(node.range[0], node.range[1]),
+            //   output: final,
+            // })
+            return fixer.replaceTextRange([node.range[0], node.range[1]], final)
+          },
+        })
+      },
+    }
+  },
+})