feat: add flat config support

.changeset/great-dodos-dream.md

@@ -0,0 +1,14 @@
+---
+"eslint-plugin-import-x": minor
+---
+
+Add ESLint flat configuration presets. You can access them with:
+
+```ts
+import eslintPluginImportX from 'eslint-plugin-import-x';
+
+eslintPluginImportX.flatConfigs.recommended;
+eslintPluginImportX.flatConfigs.react;
+eslintPluginImportX.flatConfigs.typescript;
+eslintPluginImportX.flatConfigs.electron;
+```

package.json

@@ -35,7 +35,7 @@
     "codesandbox:install": "yarn --ignore-engines",
     "lint": "run-p lint:*",
     "lint:docs": "yarn update:eslint-docs --check",
-    "lint:es": "ESLINT_USE_FLAT_CONFIG=false eslint . --cache",
+    "lint:es": "cross-env ESLINT_USE_FLAT_CONFIG=false eslint . --cache",
     "lint:tsc": "tsc -p tsconfig.base.json --noEmit",
     "prepare": "patch-package",
     "release": "changeset publish",

src/config/flat/electron.ts

@@ -0,0 +1,10 @@
+import type { PluginFlatConfig } from '../../types'
+
+/**
+ * Default settings for Electron applications.
+ */
+export default {
+  settings: {
+    'import-x/core-modules': ['electron'],
+  },
+} satisfies PluginFlatConfig

src/config/flat/errors.ts

@@ -0,0 +1,15 @@
+import type { PluginFlatConfig } from '../../types'
+
+/**
+ * unopinionated config. just the things that are necessarily runtime errors
+ * waiting to happen.
+ */
+export default {
+  rules: {
+    'import-x/no-unresolved': 2,
+    'import-x/named': 2,
+    'import-x/namespace': 2,
+    'import-x/default': 2,
+    'import-x/export': 2,
+  },
+} satisfies PluginFlatConfig

src/config/flat/react-native.ts

@@ -0,0 +1,15 @@
+import type { PluginFlatBaseConfig } from '../../types'
+
+/**
+ * adds platform extensions to Node resolver
+ */
+export default {
+  settings: {
+    'import-x/resolver': {
+      node: {
+        // Note: will not complain if only _one_ of these files exists.
+        extensions: ['.js', '.web.js', '.ios.js', '.android.js'],
+      },
+    },
+  },
+} satisfies PluginFlatBaseConfig

src/config/flat/react.ts

@@ -0,0 +1,21 @@
+import type { PluginFlatBaseConfig } from '../../types'
+
+/**
+ * Adds `.jsx` as an extension, and enables JSX parsing.
+ *
+ * Even if _you_ aren't using JSX (or .jsx) directly, if your dependencies
+ * define jsnext:main and have JSX internally, you may run into problems
+ * if you don't enable these settings at the top level.
+ */
+export default {
+  settings: {
+    'import-x/extensions': ['.js', '.jsx', '.mjs', '.cjs'],
+  },
+  languageOptions: {
+    parserOptions: {
+      ecmaFeatures: {
+        jsx: true,
+      },
+    },
+  },
+} satisfies PluginFlatBaseConfig

src/config/flat/recommended.ts

@@ -0,0 +1,27 @@
+import type { PluginFlatBaseConfig } from '../../types'
+
+/**
+ * The basics.
+ */
+export default {
+  rules: {
+    // analysis/correctness
+    'import-x/no-unresolved': 'error',
+    'import-x/named': 'error',
+    'import-x/namespace': 'error',
+    'import-x/default': 'error',
+    'import-x/export': 'error',
+
+    // red flags (thus, warnings)
+    'import-x/no-named-as-default': 'warn',
+    'import-x/no-named-as-default-member': 'warn',
+    'import-x/no-duplicates': 'warn',
+  },
+
+  // need all these for parsing dependencies (even if _your_ code doesn't need
+  // all of them)
+  languageOptions: {
+    ecmaVersion: 2018,
+    sourceType: 'module',
+  },
+} satisfies PluginFlatBaseConfig

src/config/flat/stage-0.ts

@@ -0,0 +1,12 @@
+import type { PluginFlatBaseConfig } from '../../types'
+
+/**
+ * Rules in progress.
+ *
+ * Do not expect these to adhere to semver across releases.
+ */
+export default {
+  rules: {
+    'import-x/no-deprecated': 1,
+  },
+} satisfies PluginFlatBaseConfig

src/config/flat/typescript.ts

@@ -0,0 +1,41 @@
+import type { PluginFlatBaseConfig } from '../../types'
+
+/**
+ * This config:
+ * 1) adds `.jsx`, `.ts`, `.cts`, `.mts`, and `.tsx` as an extension
+ * 2) enables JSX/TSX parsing
+ */
+
+// Omit `.d.ts` because 1) TypeScript compilation already confirms that
+// types are resolved, and 2) it would mask an unresolved
+// `.ts`/`.tsx`/`.js`/`.jsx` implementation.
+const typeScriptExtensions = ['.ts', '.tsx', '.cts', '.mts'] as const
+
+const allExtensions = [
+  ...typeScriptExtensions,
+  '.js',
+  '.jsx',
+  '.cjs',
+  '.mjs',
+] as const
+
+export default {
+  settings: {
+    'import-x/extensions': allExtensions,
+    'import-x/external-module-folders': ['node_modules', 'node_modules/@types'],
+    'import-x/parsers': {
+      '@typescript-eslint/parser': [...typeScriptExtensions],
+    },
+    'import-x/resolver': {
+      node: {
+        extensions: allExtensions,
+      },
+    },
+  },
+  rules: {
+    // analysis/correctness
+
+    // TypeScript compilation already ensures that named imports exist in the referenced module
+    'import-x/named': 'off',
+  },
+} satisfies PluginFlatBaseConfig

src/config/flat/warnings.ts

@@ -0,0 +1,12 @@
+import type { PluginFlatBaseConfig } from '../../types'
+
+/**
+ * more opinionated config.
+ */
+export default {
+  rules: {
+    'import-x/no-named-as-default': 1,
+    'import-x/no-named-as-default-member': 1,
+    'import-x/no-duplicates': 1,
+  },
+} satisfies PluginFlatBaseConfig

src/config/typescript.ts

@@ -9,16 +9,22 @@ import type { PluginConfig } from '../types'
 // Omit `.d.ts` because 1) TypeScript compilation already confirms that
 // types are resolved, and 2) it would mask an unresolved
 // `.ts`/`.tsx`/`.js`/`.jsx` implementation.
-const typeScriptExtensions = ['.ts', '.tsx'] as const
+const typeScriptExtensions = ['.ts', '.tsx', '.cts', '.mts'] as const
 
-const allExtensions = [...typeScriptExtensions, '.js', '.jsx'] as const
+const allExtensions = [
+  ...typeScriptExtensions,
+  '.js',
+  '.jsx',
+  '.cjs',
+  '.mjs',
+] as const
 
 export = {
   settings: {
     'import-x/extensions': allExtensions,
     'import-x/external-module-folders': ['node_modules', 'node_modules/@types'],
     'import-x/parsers': {
-      '@typescript-eslint/parser': [...typeScriptExtensions, '.cts', '.mts'],
+      '@typescript-eslint/parser': [...typeScriptExtensions],
     },
     'import-x/resolver': {
       node: {

src/index.ts

@@ -1,14 +1,25 @@
 import type { TSESLint } from '@typescript-eslint/utils'
 
-// rules
+import { name, version } from '../package.json'
+
 import electron from './config/electron'
 import errors from './config/errors'
+import electronFlat from './config/flat/electron'
+import errorsFlat from './config/flat/errors'
+import reactFlat from './config/flat/react'
+import reactNativeFlat from './config/flat/react-native'
+import recommendedFlat from './config/flat/recommended'
+import stage0Flat from './config/flat/stage-0'
+import typescriptFlat from './config/flat/typescript'
+import warningsFlat from './config/flat/warnings'
 import react from './config/react'
 import reactNative from './config/react-native'
 import recommended from './config/recommended'
 import stage0 from './config/stage-0'
 import typescript from './config/typescript'
 import warnings from './config/warnings'
+
+// rules
 import consistentTypeSpecifierStyle from './rules/consistent-type-specifier-style'
 import default_ from './rules/default'
 import dynamicImportChunkname from './rules/dynamic-import-chunkname'
@@ -55,23 +66,11 @@
 import preferDefaultExport from './rules/prefer-default-export'
 import unambiguous from './rules/unambiguous'
 // configs
-import type { PluginConfig } from './types'
-
-const configs = {
-  recommended,
-
-  errors,
-  warnings,
-
-  // shhhh... work in progress "secret" rules
-  'stage-0': stage0,
-
-  // useful stuff for folks using various environments
-  react,
-  'react-native': reactNative,
-  electron,
-  typescript,
-} satisfies Record<string, PluginConfig>
+import type {
+  PluginConfig,
+  PluginFlatBaseConfig,
+  PluginFlatConfig,
+} from './types'
 
 const rules = {
   'no-unresolved': noUnresolved,
@@ -129,7 +128,56 @@
   'imports-first': importsFirst,
 } satisfies Record<string, TSESLint.RuleModule<string, readonly unknown[]>>
 
+const configs = {
+  recommended,
+
+  errors,
+  warnings,
+
+  // shhhh... work in progress "secret" rules
+  'stage-0': stage0,
+
+  // useful stuff for folks using various environments
+  react,
+  'react-native': reactNative,
+  electron,
+  typescript,
+} satisfies Record<string, PluginConfig>
+
+// Base Plugin Object
+const plugin = {
+  meta: { name, version },
+  rules,
+}
+
+// Create flat configs (Only ones that declare plugins and parser options need to be different from the legacy config)
+const createFlatConfig = (
+  baseConfig: PluginFlatBaseConfig,
+  configName: string,
+): PluginFlatConfig => ({
+  ...baseConfig,
+  name: `import-x/${configName}`,
+  plugins: { 'import-x': plugin },
+})
+
+const flatConfigs = {
+  recommended: createFlatConfig(recommendedFlat, 'recommended'),
+
+  errors: createFlatConfig(errorsFlat, 'errors'),
+  warnings: createFlatConfig(warningsFlat, 'warnings'),
+
+  // shhhh... work in progress "secret" rules
+  'stage-0': createFlatConfig(stage0Flat, 'stage-0'),
+
+  // useful stuff for folks using various environments
+  react: reactFlat,
+  'react-native': reactNativeFlat,
+  electron: electronFlat,
+  typescript: typescriptFlat,
+} satisfies Record<string, PluginFlatConfig>
+
 export = {
   configs,
+  flatConfigs,
   rules,
 }

src/types.ts

@@ -70,6 +70,15 @@ export type PluginConfig = {
   rules?: Record<`${PluginName}/${string}`, TSESLint.Linter.RuleEntry>
 } & TSESLint.Linter.ConfigType
 
+export type PluginFlatBaseConfig = {
+  settings?: PluginSettings
+  rules?: Record<`${PluginName}/${string}`, TSESLint.FlatConfig.RuleEntry>
+} & TSESLint.FlatConfig.Config
+
+export type PluginFlatConfig = PluginFlatBaseConfig & {
+  name?: `${PluginName}/${string}`
+}
+
 export type RuleContext<
   TMessageIds extends string = string,
   TOptions extends readonly unknown[] = readonly unknown[],

src/utils/ignore.ts

@@ -28,7 +28,7 @@ function validExtensions(context: ChildContext | RuleContext) {
 export function getFileExtensions(settings: PluginSettings) {
   // start with explicit JS-parsed extensions
   const exts = new Set<FileExtension>(
-    settings['import-x/extensions'] || ['.js'],
+    settings['import-x/extensions'] || ['.js', '.mjs', '.cjs'],
   )
 
   // all alternate parser extensions are also valid