break(eslint-plugin): Add ESLint flag configs, require ESLint >= 8.57

packages/eslint-plugin/package.json

@@ -18,17 +18,20 @@
   },
   "license": "MIT",
   "scripts": {
-    "build": "tsc"
+    "build": "tsc",
+    "watch": "tsc --watch"
   },
   "dependencies": {
-    "@typescript-eslint/utils": "^5.62.0",
+    "@typescript-eslint/utils": "^8.59.3",
+    "@typescript-eslint/types": "^8.59.3",
     "tslib": "^2.6.0"
   },
   "devDependencies": {
-    "eslint-plugin-eslint-plugin": "^5.1.0"
+    "@typescript-eslint/rule-tester": "^8.59.3",
+    "eslint-plugin-eslint-plugin": "^6.5.0"
   },
   "peerDependencies": {
-    "eslint": ">=6"
+    "eslint": ">=8.57.0"
   },
   "engines": {
     "node": ">=24.14"

packages/eslint-plugin/src/index.ts

@@ -5,28 +5,57 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import {name, version} from '../package.json';
+
 import rules from './rules';
 
-// @ts-expect-error: TODO try to remove later
-export = {
+const plugin = {
+  meta: {name, version, namespace: '@docusaurus'},
   rules,
+};
+
+const rulesRecommended = {
+  '@docusaurus/string-literal-i18n-messages': 'error',
+  '@docusaurus/no-html-links': 'warn',
+  '@docusaurus/prefer-docusaurus-heading': 'warn',
+};
+
+const rulesAll = {
+  '@docusaurus/string-literal-i18n-messages': 'error',
+  '@docusaurus/no-untranslated-text': 'warn',
+  '@docusaurus/no-html-links': 'warn',
+  '@docusaurus/prefer-docusaurus-heading': 'warn',
+};
+
+// Supports both legacy/flat configs:
+// https://eslint.org/docs/latest/extend/plugins#backwards-compatibility-for-legacy-configs
+const compatPlugin = {
+  ...plugin,
   configs: {
     recommended: {
       plugins: ['@docusaurus'],
-      rules: {
-        '@docusaurus/string-literal-i18n-messages': 'error',
-        '@docusaurus/no-html-links': 'warn',
-        '@docusaurus/prefer-docusaurus-heading': 'warn',
-      },
+      rules: rulesRecommended,
     },
     all: {
       plugins: ['@docusaurus'],
-      rules: {
-        '@docusaurus/string-literal-i18n-messages': 'error',
-        '@docusaurus/no-untranslated-text': 'warn',
-        '@docusaurus/no-html-links': 'warn',
-        '@docusaurus/prefer-docusaurus-heading': 'warn',
+      rules: rulesAll,
+    },
+    flat: {
+      recommended: {
+        plugins: {
+          '@docusaurus': plugin,
+        },
+        rules: rulesRecommended,
+      },
+      all: {
+        plugins: {
+          '@docusaurus': plugin,
+        },
+        rules: rulesAll,
       },
     },
   },
 };
+
+// @ts-expect-error: TODO try to remove later
+export = compatPlugin;

packages/eslint-plugin/src/rules/__tests__/no-html-links.test.ts

@@ -6,19 +6,10 @@
  */
 
 import rule from '../no-html-links';
-import {RuleTester} from './testUtils';
+import {ruleTester} from './testUtils';
 
 const errorsJSX = [{messageId: 'link'}] as const;
 
-const ruleTester = new RuleTester({
-  parser: '@typescript-eslint/parser',
-  parserOptions: {
-    ecmaFeatures: {
-      jsx: true,
-    },
-  },
-});
-
 ruleTester.run('prefer-docusaurus-link', rule, {
   valid: [
     {

packages/eslint-plugin/src/rules/__tests__/no-untranslated-text.test.ts

@@ -6,19 +6,10 @@
  */
 
 import rule from '../no-untranslated-text';
-import {getCommonValidTests, RuleTester} from './testUtils';
+import {getCommonValidTests, ruleTester} from './testUtils';
 
 const errorsJSX = [{messageId: 'translateChildren'}] as const;
 
-const ruleTester = new RuleTester({
-  parser: '@typescript-eslint/parser',
-  parserOptions: {
-    ecmaFeatures: {
-      jsx: true,
-    },
-  },
-});
-
 ruleTester.run('no-untranslated-text', rule, {
   valid: [
     ...getCommonValidTests(),

packages/eslint-plugin/src/rules/__tests__/prefer-docusaurus-heading.test.ts

@@ -6,19 +6,10 @@
  */
 
 import rule from '../prefer-docusaurus-heading';
-import {RuleTester} from './testUtils';
+import {ruleTester} from './testUtils';
 
 const errorsJSX = [{messageId: 'headings'}] as const;
 
-const ruleTester = new RuleTester({
-  parser: '@typescript-eslint/parser',
-  parserOptions: {
-    ecmaFeatures: {
-      jsx: true,
-    },
-  },
-});
-
 ruleTester.run('prefer-docusaurus-heading', rule, {
   valid: [
     {

packages/eslint-plugin/src/rules/__tests__/string-literal-i18n-messages.test.ts

@@ -6,20 +6,11 @@
  */
 
 import rule from '../string-literal-i18n-messages';
-import {getCommonValidTests, RuleTester} from './testUtils';
+import {getCommonValidTests, ruleTester} from './testUtils';
 
 const errorsJSX = [{messageId: 'translateChildren'}] as const;
 const errorsFunc = [{messageId: 'translateArg'}] as const;
 
-const ruleTester = new RuleTester({
-  parser: '@typescript-eslint/parser',
-  parserOptions: {
-    ecmaFeatures: {
-      jsx: true,
-    },
-  },
-});
-
 ruleTester.run('string-literal-i18n-messages', rule, {
   valid: [...getCommonValidTests()],
 

packages/eslint-plugin/src/rules/__tests__/testUtils.ts

@@ -6,9 +6,7 @@
  */
 
 import {afterAll, describe, it} from 'vitest';
-import {ESLintUtils} from '@typescript-eslint/utils';
-
-const {RuleTester} = ESLintUtils;
+import {RuleTester} from '@typescript-eslint/rule-tester';
 
 // `RuleTester` defers to globals when these are unset; we run with
 // `globals: false`, so wire it to Vitest's test-framework functions instead.
@@ -17,7 +15,15 @@ RuleTester.describe = describe;
 RuleTester.it = it;
 RuleTester.itOnly = it.only;
 
-export {RuleTester};
+export const ruleTester = new RuleTester({
+  languageOptions: {
+    parserOptions: {
+      ecmaFeatures: {
+        jsx: true,
+      },
+    },
+  },
+});
 
 export const getCommonValidTests = (): {code: string}[] => [
   {

packages/eslint-plugin/src/rules/no-html-links.ts

@@ -6,7 +6,7 @@
  */
 
 import {createRule} from '../util';
-import type {TSESTree} from '@typescript-eslint/types/dist/ts-estree';
+import type {TSESTree} from '@typescript-eslint/types';
 
 const docsUrl = 'https://docusaurus.io/docs/docusaurus-core#link';
 

packages/eslint-plugin/src/rules/no-untranslated-text.ts

@@ -6,7 +6,7 @@
  */
 
 import {isTextLabelChild, createRule} from '../util';
-import type {TSESTree} from '@typescript-eslint/types/dist/ts-estree';
+import type {TSESTree} from '@typescript-eslint/types';
 
 type Options = [
   {

packages/eslint-plugin/src/rules/prefer-docusaurus-heading.ts

@@ -6,7 +6,7 @@
  */
 
 import {createRule} from '../util';
-import type {TSESTree} from '@typescript-eslint/types/dist/ts-estree';
+import type {TSESTree} from '@typescript-eslint/types';
 
 type Options = [];
 type MessageIds = 'headings';

packages/eslint-plugin/src/rules/string-literal-i18n-messages.ts

@@ -10,7 +10,7 @@ import {
   isStringWithoutExpressions,
   createRule,
 } from '../util';
-import type {TSESTree} from '@typescript-eslint/types/dist/ts-estree';
+import type {TSESTree} from '@typescript-eslint/types';
 
 type Options = [];
 type MessageIds = 'translateChildren' | 'translateArg';

packages/eslint-plugin/src/util.ts

@@ -5,8 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {ESLintUtils} from '@typescript-eslint/utils';
-import type {TSESTree} from '@typescript-eslint/types/dist/ts-estree';
+import {ESLintUtils, type TSESTree} from '@typescript-eslint/utils';
 
 type CheckTranslateChildOptions = {
   ignoredStrings?: string[];
@@ -61,7 +60,14 @@ export function isTextLabelChild(
   }
 }
 
-export const createRule = ESLintUtils.RuleCreator(
+// Not sure if we really need this
+// See https://typescript-eslint.io/blog/announcing-typescript-eslint-v8/#custom-rule-metadocs-types
+// See https://github.com/typescript-eslint/typescript-eslint/pull/9025
+export interface PluginDocs {
+  recommended: boolean | 'error';
+}
+
+export const createRule = ESLintUtils.RuleCreator<PluginDocs>(
   (name) =>
     `https://docusaurus.io/docs/api/misc/@docusaurus/eslint-plugin/${name}`,
 );

website/docs/api/misc/eslint-plugin/README.mdx

@@ -7,15 +7,77 @@ slug: /api/misc/@docusaurus/eslint-plugin
 
 [ESLint](https://eslint.org/) is a tool that statically analyzes your code and reports problems or suggests best practices through editor hints and command line. Docusaurus provides an ESLint plugin to enforce best Docusaurus practices.
 
+This ESLint plugin supports ESLint `>= 8.57.0`, flat configs and legacy configs.
+
 ## Installation {/* #installation */}
 
 ```bash npm2yarn
 npm install --save-dev @docusaurus/eslint-plugin
 ```
 
-## Usage {/* #usage */}
+## Supported configs {/* #supported-configs */}
+
+Both built-in configs exist in flat and legacy variants:
+
+- Recommended: recommended rule set for most Docusaurus sites that should be extended from.
+- All: **all** rules enabled. This will change between minor versions, so you should not use this if you want to avoid unexpected breaking changes.
+
+## Supported rules {/* #supported-rules */}
+
+| Name | Description |  |
+| --- | --- | --- |
+| [`@docusaurus/no-untranslated-text`](./no-untranslated-text.mdx) | Enforce text labels in JSX to be wrapped by translate calls |  |
+| [`@docusaurus/string-literal-i18n-messages`](./string-literal-i18n-messages.mdx) | Enforce translate APIs to be called on plain text labels | ✅ |
+| [`@docusaurus/no-html-links`](./no-html-links.mdx) | Ensures @docusaurus/Link is used instead of `<a>` tags | ✅ |
+| [`@docusaurus/prefer-docusaurus-heading`](./prefer-docusaurus-heading.mdx) | Ensures @theme/Heading is used instead of `<hn>` tags for headings | ✅ |
+
+✅ = recommended
+
+## Usage - Flat {/* #usage-flat */}
+
+### Recommended config {/* #recommended-config-flat */}
+
+Import `@docusaurus/eslint-plugin` and add `docusaurus.configs.flat.recommended` to your flat config array:
+
+```js title="eslint.config.js"
+import {defineConfig} from 'eslint/config';
+// highlight-next-line
+import docusaurus from '@docusaurus/eslint-plugin';
+
+export default defineConfig(
+  // highlight-next-line
+  docusaurus.configs.flat.recommended,
+  {
+    // Other config
+  },
+);
+```
+
+This will enable the `@docusaurus` eslint plugin and use the `recommended` config. See [Supported rules](#supported-rules) above for a list of rules that this will enable.
+
+### Manual config {/* #manual-config-flat */}
+
+For more fine-grained control, you can also enable the plugin manually and configure the rules you want to use directly:
+
+```js title="eslint.config.js"
+import {defineConfig} from 'eslint/config';
+// highlight-next-line
+import docusaurus from '@docusaurus/eslint-plugin';
+
+export default defineConfig({
+  // highlight-start
+  plugins: {docusaurus},
+  rules: {
+    '@docusaurus/string-literal-i18n-messages': 'error',
+    '@docusaurus/no-untranslated-text': 'warn',
+  },
+  // highlight-end
+});
+```
+
+## Usage - Legacy {/* #usage-legacy */}
 
-### Recommended config {/* #recommended-config */}
+### Recommended config {/* #recommended-config-legacy */}
 
 Add `plugin:@docusaurus/recommended` to the `extends` section of your `.eslintrc` configuration file:
 
@@ -25,9 +87,9 @@ Add `plugin:@docusaurus/recommended` to the `extends` section of your `.eslintrc
 }
 ```
 
-This will enable the `@docusaurus` eslint plugin and use the `recommended` config. See [Supported rules](#supported-rules) below for a list of rules that this will enable.
+This will enable the `@docusaurus` eslint plugin and use the `recommended` config. See [Supported rules](#supported-rules) above for a list of rules that this will enable.
 
-### Manual config {/* #manual-config */}
+### Manual config {/* #manual-config-legacy */}
 
 For more fine-grained control, you can also enable the plugin manually and configure the rules you want to use directly:
 
@@ -40,35 +102,3 @@ For more fine-grained control, you can also enable the plugin manually and confi
   }
 }
 ```
-
-## Supported configs {/* #supported-configs */}
-
-- Recommended: recommended rule set for most Docusaurus sites that should be extended from.
-- All: **all** rules enabled. This will change between minor versions, so you should not use this if you want to avoid unexpected breaking changes.
-
-## Supported rules {/* #supported-rules */}
-
-| Name | Description |  |
-| --- | --- | --- |
-| [`@docusaurus/no-untranslated-text`](./no-untranslated-text.mdx) | Enforce text labels in JSX to be wrapped by translate calls |  |
-| [`@docusaurus/string-literal-i18n-messages`](./string-literal-i18n-messages.mdx) | Enforce translate APIs to be called on plain text labels | ✅ |
-| [`@docusaurus/no-html-links`](./no-html-links.mdx) | Ensures @docusaurus/Link is used instead of `<a>` tags | ✅ |
-| [`@docusaurus/prefer-docusaurus-heading`](./prefer-docusaurus-heading.mdx) | Ensures @theme/Heading is used instead of `<hn>` tags for headings | ✅ |
-
-✅ = recommended
-
-## Example configuration {/* #example-configuration */}
-
-Here's an example configuration:
-
-```js title=".eslintrc.js"
-module.exports = {
-  extends: ['plugin:@docusaurus/recommended'],
-  rules: {
-    '@docusaurus/no-untranslated-text': [
-      'warn',
-      {ignoredStrings: ['·', '—', '×']},
-    ],
-  },
-};
-```