feat: introduce flat config

README.md

@@ -59,6 +59,14 @@ module.exports = {
 };
 ```
 
+**eslint.config.js**
+```js
+const algolia = require('eslint-config-algolia/flat/base');
+module.exports = [
+  ...algolia,
+];
+```
+
 **package.json**
 ```json
 {
@@ -86,6 +94,16 @@ module.exports = {
 };
 ```
 
+**eslint.config.js**
+```js
+const algolia = require('eslint-config-algolia/flat/base');
+const algoliaJest = require('eslint-config-algolia/flat/jest');
+module.exports = [
+  ...algolia,
+  ...algoliaJest,
+];
+```
+
 **package.json**
 ```json
 {
@@ -111,6 +129,16 @@ module.exports = {
 };
 ```
 
+**eslint.config.js**
+```js
+const algolia = require('eslint-config-algolia/flat/base');
+const algoliaReact = require('eslint-config-algolia/flat/react');
+module.exports = [
+  ...algolia,
+  ...algoliaReact,
+];
+```
+
 **package.json**
 ```json
 {
@@ -122,7 +150,7 @@ module.exports = {
 }
 ```
 
-### Flow
+### Flow (deprecated)
 
 **terminal**
 ```sh
@@ -136,7 +164,7 @@ module.exports = {
 };
 ```
 
-### Flow with React
+### Flow with React (deprecated)
 
 **terminal**
 ```sh
@@ -171,14 +199,31 @@ yarn add @typescript-eslint/parser @typescript-eslint/eslint-plugin typescript -
 **.eslintrc.js**
 ```js
 module.exports = {
-  extends: ['algolia', 'algolia/typescript']
+  extends: ['algolia', 'algolia/typescript'],
 
   parserOptions: {
     project: '<path-to-tsconfig.json>',
   },
 };
 ```
 
+**eslint.config.js**
+```js
+const algolia = require('eslint-config-algolia/flat/base');
+const algoliaTypescript = require('eslint-config-algolia/flat/typescript');
+module.exports = [
+  ...algolia,
+  ...algoliaTypescript,
+  {
+    languageOptions: {
+      parserOptions: {
+        project: '<path-to-tsconfig.json>',
+      },
+    },
+  },
+];
+```
+
 **package.json**
 ```json
 {
@@ -207,6 +252,18 @@ module.exports = {
 ```
 **Note**: Be sure to put the `algolia/typescript` configuration last so the parser is properly set for TypeScript files.
 
+**eslint.config.js**
+```js
+const algolia = require('eslint-config-algolia/flat/base');
+const algoliaReact = require('eslint-config-algolia/flat/react');
+const algoliaTypescript = require('eslint-config-algolia/flat/typescript');
+module.exports = [
+  ...algolia,
+  ...algoliaReact,
+  ...algoliaTypescript,
+];
+```
+
 **package.json**
 ```json
 {
@@ -233,6 +290,16 @@ module.exports = {
 };
 ```
 
+**eslint.config.js**
+```js
+const algolia = require('eslint-config-algolia/flat/base');
+const algoliaVue = require('eslint-config-algolia/flat/vue');
+module.exports = [
+  ...algolia,
+  ...algoliaVue,
+];
+```
+
 **package.json**
 ```json
 {
@@ -275,10 +342,23 @@ module.exports = {
   extends: 'algolia',
   rules: {
     'import/no-commonjs': 'off'
-  }
+  },
 };
 ```
 
+**eslint.config.js**
+```js
+const algolia = require('eslint-config-algolia/flat/base');
+module.exports = [
+  ...algolia,
+  {
+    rules: {
+      'import/no-commonjs': 'off'
+    }
+  },
+];
+```
+
 ## Existing codebase setup
 
 If you have a lot of files already written and wants to now use

packages/eslint-config-algolia/eslint.config.js

@@ -0,0 +1,4 @@
+/* eslint-disable import/no-commonjs */
+const base = require('./flat/base');
+
+module.exports = [...base];

packages/eslint-config-algolia/flat/base.js

@@ -0,0 +1,61 @@
+/* eslint-disable import/no-commonjs */
+const eslintJs = require('@eslint/js');
+const commentsPlugin = require('@eslint-community/eslint-plugin-eslint-comments');
+const stylisticPlugin = require('@stylistic/eslint-plugin');
+const importPlugin = require('eslint-plugin-import');
+const jsdocPlugin = require('eslint-plugin-jsdoc');
+const eslintPluginPrettierRecommended = require('eslint-plugin-prettier/recommended');
+const reactHooksPlugin = require('eslint-plugin-react-hooks');
+const globals = require('globals');
+
+const rules = require('../rules/base');
+
+// Remove legacy properties
+delete rules.overrides;
+
+module.exports = [
+  eslintJs.configs.recommended,
+  rules,
+  // prettier is set after to override our own rules
+  eslintPluginPrettierRecommended,
+  {
+    plugins: {
+      '@stylistic': stylisticPlugin,
+      '@eslint-community/eslint-comments': commentsPlugin,
+      import: importPlugin,
+      jsdoc: jsdocPlugin,
+      'react-hooks': reactHooksPlugin,
+    },
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+      },
+      ecmaVersion: 'latest',
+      sourceType: 'module',
+      parserOptions: {
+        ecmaFeatures: {
+          experimentalObjectRestSpread: true,
+          impliedStrict: true,
+        },
+      },
+    },
+    settings: {
+      'import/extensions': ['.js', '.jsx', '.ts', '.tsx'],
+
+      'import/resolver': {
+        node: {
+          extensions: ['.js', '.jsx', '.ts', '.tsx'],
+        },
+      },
+    },
+  },
+  // Mixed codebase issues
+  {
+    // enable the rule specifically for TypeScript files
+    files: ['*.ts', '*.tsx'],
+    rules: {
+      'jsdoc/no-types': ['error'],
+    },
+  },
+];

packages/eslint-config-algolia/flat/jest.js

@@ -0,0 +1,18 @@
+/* eslint-disable import/no-commonjs */
+const jestPlugin = require('eslint-plugin-jest');
+const globals = require('globals');
+
+const jestRules = require('../rules/jest');
+
+module.exports = [
+  jestRules,
+  {
+    ...jestPlugin.configs['flat/recommended'],
+    ...jestPlugin.configs['flat/style'],
+    languageOptions: {
+      globals: {
+        ...globals.jest,
+      },
+    },
+  },
+];

packages/eslint-config-algolia/flat/react.js

@@ -0,0 +1,28 @@
+/* eslint-disable import/no-commonjs */
+const babelParser = require('@babel/eslint-parser');
+const jsxA11yPlugin = require('eslint-plugin-jsx-a11y');
+const reactPlugin = require('eslint-plugin-react');
+const reactHooksPlugin = require('eslint-plugin-react-hooks');
+
+const rules = require('../rules/react');
+
+module.exports = [
+  reactPlugin.configs.flat.recommended,
+  {
+    plugins: {
+      'react-hooks': reactHooksPlugin,
+      'jsx-a11y': jsxA11yPlugin,
+    },
+
+    languageOptions: {
+      parser: babelParser,
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+        requireConfigFile: false,
+      },
+    },
+  },
+  rules,
+];

packages/eslint-config-algolia/flat/typescript.js

@@ -0,0 +1,48 @@
+/* eslint-disable import/no-commonjs */
+const typescriptPlugin = require('@typescript-eslint/eslint-plugin');
+const parser = require('@typescript-eslint/parser');
+const importPlugin = require('eslint-plugin-import');
+
+const rules = require('../rules/typescript');
+
+// Remove legacy properties
+delete rules.plugins;
+delete rules.overrides;
+
+module.exports = [
+  rules,
+  {
+    plugins: {
+      '@typescript-eslint': typescriptPlugin,
+      import: importPlugin,
+    },
+    languageOptions: {
+      parser,
+      parserOptions: {
+        ecmaFeatures: {
+          impliedStrict: true,
+          jsx: true,
+        },
+        ecmaVersion: 2018,
+        sourceType: 'module',
+        requireConfigFile: false,
+      },
+    },
+  },
+  // Mixed codebase issues
+  {
+    // enable the rule specifically for TypeScript files
+    files: ['*.ts', '*.tsx'],
+    rules: {
+      '@typescript-eslint/explicit-function-return-type': [
+        'error',
+        {
+          allowHigherOrderFunctions: true,
+          allowTypedFunctionExpressions: true,
+          // allowExpressions: true,
+        },
+      ],
+      '@typescript-eslint/explicit-member-accessibility': ['error', { accessibility: 'no-public' }],
+    },
+  },
+];

packages/eslint-config-algolia/flat/vue.js

@@ -0,0 +1,40 @@
+// We don't extends from the `base` preset because the Vue plugin needs
+// to use the parser under `parserOptions`. By doing this we broke the import
+// plugin in the `react` preset. For now we just recreate the same configuration
+// until all the plugins behave the same.
+
+/* eslint-disable import/no-commonjs */
+const babelParser = require('@babel/eslint-parser');
+const importPlugin = require('eslint-plugin-import');
+const vuePlugin = require('eslint-plugin-vue');
+const globals = require('globals');
+
+const rules = require('../rules/vue');
+
+module.exports.flat = [
+  ...vuePlugin.configs['flat/recommended'],
+  rules,
+  {
+    plugins: {
+      import: importPlugin,
+    },
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+      },
+      ecmaVersion: 2018,
+      sourceType: 'module',
+      parser: babelParser, // allows both flowtype and static class properties
+      parserOptions: {
+        ecmaFeatures: {
+          impliedStrict: true,
+          jsx: true,
+        },
+      },
+    },
+    settings: {
+      'import/extensions': ['.js'],
+    },
+  },
+];

packages/eslint-config-algolia/package.json

@@ -27,6 +27,7 @@
     "@babel/core": "7.25.2",
     "@babel/eslint-parser": "7.25.1",
     "@eslint-community/eslint-plugin-eslint-comments": "4.4.0",
+    "@eslint/js": "9.11.1",
     "@stylistic/eslint-plugin": "2.7.2",
     "eslint": "8.57.0",
     "eslint-config-prettier": "8.10.0",
@@ -37,6 +38,7 @@
     "eslint-plugin-prettier": "5.2.1",
     "eslint-plugin-react": "7.35.0",
     "eslint-plugin-react-hooks": "4.6.2",
+    "globals": "15.10.0",
     "prettier": "3.3.3"
   },
   "peerDependencies": {