Support both flat and legacy ESLint configuration styles 🥙

.eslintrc

@@ -0,0 +1,16 @@
+{
+  "extends": [
+    "./lib/all-legacy"
+  ],
+  "rules": {
+    // "semi": [1, "always"]
+  },
+  "parserOptions": {
+    "ecmaFeatures": {
+      "modules": true
+    },
+    "ecmaVersion": 2018,
+    "requireConfigFile": false,
+    "sourceType": "module"
+  }
+}

.github/workflows/test.yml

@@ -27,6 +27,9 @@ jobs:
     - name: Install Dependencies
       run: yarn install --immutable
 
+    - name: Lint
+      run: yarn lint --ignore-patterns '**/*.ts'
+
     - name: Run Tests
       run: yarn test --coverage
 

config/all-legacy.ts

@@ -0,0 +1,3 @@
+import buildLegacyConfig from './eslint/build-legacy-config'
+
+export default buildLegacyConfig()

config/all.ts

@@ -1,3 +1,3 @@
-import buildConfig from './eslint/build-config'
+import buildFlatConfig from './eslint/build-flat-config'
 
-export default buildConfig()
+export default buildFlatConfig()

config/eslint/build-flat-config.ts

@@ -0,0 +1,42 @@
+import { FILE_PATHS } from './constants'
+import Plugins from './plugins'
+import Rules from './rules'
+
+const buildFlatConfig = () => ([{
+  plugins: {
+    'eslint-comments': Plugins.EslintComments,
+    'inclusive-language': Plugins.InclusiveLanguage,
+    'promise': Plugins.Promise,
+    'sort-destructure-keys': Plugins.SortDestructureKeys,
+    'sort-exports': Plugins.SortExports,
+  },
+  rules: {
+    ...Rules.ESLintComments,
+    ...Rules.InclusiveLanguage,
+    ...Rules.Promise,
+    ...Rules.SortDestructureKeys,
+    ...Rules.SortExports,
+  },
+}, {
+  files: FILE_PATHS.TESTS,
+  languageOptions: {
+    globals: {
+      'jest/globals': true,
+    },
+  },
+  plugins: {
+    'jest': Plugins.Jest,
+    'jest-formatting': Plugins.JestFormatting,
+  },
+  rules: {
+    ...Rules.Jest,
+    ...Rules.JestFormatting,
+  },
+}, {
+  files: FILE_PATHS.TESTS_TYPESCRIPT,
+  rules: {
+    ...Rules.JestTypescript,
+  },
+}])
+
+export default buildFlatConfig

config/eslint/build-legacy-config.ts

@@ -0,0 +1,40 @@
+import { FILE_PATHS } from './constants'
+import Rules from './rules'
+
+const buildLegacyConfig = () => ({
+  env: {
+    'jest/globals': true,
+  },
+  plugins: [
+    'eslint-comments',
+    'inclusive-language',
+    'promise',
+    'sort-destructure-keys',
+    'sort-exports',
+  ],
+  rules: {
+    ...Rules.ESLintComments,
+    ...Rules.InclusiveLanguage,
+    ...Rules.Promise,
+    ...Rules.SortDestructureKeys,
+    ...Rules.SortExports,
+  },
+  overrides: [{
+    files: FILE_PATHS.TESTS,
+    plugins: [
+      'jest',
+      'jest-formatting',
+    ],
+    rules: {
+      ...Rules.Jest,
+      ...Rules.JestFormatting,
+    },
+  }, {
+    files: FILE_PATHS.TESTS_TYPESCRIPT,
+    rules: {
+      ...Rules.JestTypescript,
+    },
+  }],
+})
+
+export default buildLegacyConfig

config/eslint/constants.ts

@@ -0,0 +1,16 @@
+const FILE_PATHS = {
+  TESTS: [
+    '*.spec.*',
+    '*.test.*',
+  ],
+  TESTS_TYPESCRIPT: [
+    '*.spec.ts',
+    '*.spec.tsx',
+    '*.test.ts',
+    '*.test.tsx',
+  ]
+}
+
+export {
+  FILE_PATHS,
+}

config/eslint/plugins.ts

@@ -0,0 +1,21 @@
+// @ts-nocheck
+
+import EslintComments from 'eslint-plugin-eslint-comments'
+import InclusiveLanguage from 'eslint-plugin-inclusive-language'
+import Jest from 'eslint-plugin-jest'
+import JestFormatting from 'eslint-plugin-jest-formatting'
+import Promise from 'eslint-plugin-promise'
+import SortDestructureKeys from 'eslint-plugin-sort-destructure-keys'
+import SortExports from 'eslint-plugin-sort-exports'
+
+const Plugins = {
+  EslintComments,
+  InclusiveLanguage,
+  Jest,
+  JestFormatting,
+  Promise,
+  SortDestructureKeys,
+  SortExports,
+}
+
+export default Plugins

config/eslint/rules/index.ts

@@ -0,0 +1,20 @@
+import ESLintComments from './eslint-comments'
+import InclusiveLanguage from './inclusive-language'
+import { Jest, JestTypescript } from './jest'
+import JestFormatting from './jest-formatting'
+import Promise from './promise'
+import SortDestructureKeys from './sort-destructure-keys'
+import SortExports from './sort-exports'
+
+const Rules = {
+  ESLintComments,
+  InclusiveLanguage,
+  Jest,
+  JestFormatting,
+  JestTypescript,
+  Promise,
+  SortDestructureKeys,
+  SortExports,
+}
+
+export default Rules

config/eslint/rules/jest.ts

@@ -1,6 +1,6 @@
 // https://github.com/jest-community/eslint-plugin-jest
 
-export const JestRules = {
+export const Jest = {
   'jest/consistent-test-it': 2,
   'jest/expect-expect': [2, {
     assertFunctionNames: ['expect', 'expect*'],
@@ -64,7 +64,7 @@ export const JestRules = {
   'jest/valid-title': 2,
 }
 
-export const JestTypescriptRules = {
+export const JestTypescript = {
   'jest/no-untyped-mock-factory': 2,
   'jest/unbound-method': 1,
 }

eslint.config.js

@@ -1,7 +1,10 @@
-export default [{
-  rules: {
-    'comma-dangle': [2, 'always-multiline'],
-    quotes: [2, 'single'],
-    semi: [2, 'never'],
-  },
-}]
+import config from './config/all.ts'
+
+export default [
+  ...config,
+  {
+    rules: {
+      // semi: [2, 'always'],
+    }
+  }
+]

package.json

@@ -24,7 +24,7 @@
     "chalk": "5.3.0",
     "chokidar": "3.6.0",
     "commander": "12.1.0",
-    "eslint": "9.4.0",
+    "eslint": "9.8.0",
     "eslint-plugin-eslint-comments": "3.2.0",
     "eslint-plugin-inclusive-language": "2.2.1",
     "eslint-plugin-jest": "28.6.0",
@@ -44,10 +44,12 @@
     "@babel/core": "7.24.6",
     "@babel/preset-env": "7.24.6",
     "@babel/preset-typescript": "7.24.7",
+    "@rollup/plugin-node-resolve": "15.2.3",
     "@rollup/plugin-replace": "5.0.7",
     "@rollup/plugin-typescript": "11.1.6",
-    "@types/eslint": "8.56.10",
+    "@types/eslint": "9.6.0",
     "@types/jest": "29.5.12",
+    "@types/markdownlint-rule-helpers": "0.21.5",
     "@types/node-notifier": "8.0.5",
     "babel-plugin-transform-import-meta": "2.2.1",
     "jest": "29.7.0",

rollup.config.js

@@ -1,6 +1,7 @@
 import { readFileSync } from 'fs'
 import { resolve } from 'path'
 
+import { nodeResolve } from '@rollup/plugin-node-resolve'
 import replace from '@rollup/plugin-replace'
 import typescript from '@rollup/plugin-typescript'
 import { terser } from 'rollup-plugin-terser'
@@ -15,6 +16,9 @@ export default {
     format: 'es',
   },
   plugins: [
+    nodeResolve({
+      preferBuiltins: true,
+    }),
     replace({
       'process.env.NODE_ENV': JSON.stringify('production'),
       preventAssignment: true,

src/index.ts

@@ -23,7 +23,7 @@ program
   .addHelpText('beforeAll', '\n✈️ Lint Pilot ✈️\n')
   .showHelpAfterError('\n💡 Run `lint-pilot --help` for more information.\n')
 
-const runLinter = async ({ cache, filePattern, fix, linter, ignore }: RunLinter) => {
+const runLinter = async ({ cache, eslintUseLegacyConfig, filePattern, fix, linter, ignore }: RunLinter) => {
   const startTime = new Date().getTime()
   colourLog.info(`Running ${linter.toLowerCase()}...`)
 
@@ -35,6 +35,7 @@ const runLinter = async ({ cache, filePattern, fix, linter, ignore }: RunLinter)
 
   const report: LintReport = await linters[linter].lintFiles({
     cache,
+    eslintUseLegacyConfig,
     files,
     fix,
   })
@@ -44,7 +45,7 @@ const runLinter = async ({ cache, filePattern, fix, linter, ignore }: RunLinter)
   return report
 }
 
-const runLintPilot = ({ cache, filePatterns, fix, title, watch }: RunLintPilot) => {
+const runLintPilot = ({ cache, eslintUseLegacyConfig, filePatterns, fix, title, watch }: RunLintPilot) => {
   const commonArgs = {
     cache,
     fix,
@@ -54,6 +55,7 @@ const runLintPilot = ({ cache, filePatterns, fix, title, watch }: RunLintPilot)
   Promise.all([
     runLinter({
       ...commonArgs,
+      eslintUseLegacyConfig,
       filePattern: filePatterns.includePatterns[Linter.ESLint],
       linter: Linter.ESLint,
     }),
@@ -96,12 +98,14 @@ program
   .option('--cache', 'cache linting results', false)
   .option('--clearCache', 'clear the cache', false)
 
-  .option('--ignore-dirs <directories...>', 'Directories to ignore globally')
-  .option('--ignore-patterns <patterns...>', 'File patterns to ignore globally')
-  .option('--eslint-include <patterns...>', 'File patterns to include for ESLint')
+  .option('--ignore-dirs <directories...>', 'directories to ignore globally')
+  .option('--ignore-patterns <patterns...>', 'file patterns to ignore globally')
+  .option('--eslint-include <patterns...>', 'file patterns to include for ESLint')
 
   .option('--debug', 'output additional debug information including the list of files being linted', false)
-  .action(({ cache, clearCache, debug, emoji, eslintInclude, fix, ignoreDirs, ignorePatterns, title, watch }) => {
+  .option('--eslint-use-legacy-config', 'set to true to use the legacy ESLint configuration', false)
+
+  .action(({ cache, clearCache, debug, emoji, eslintInclude, eslintUseLegacyConfig, fix, ignoreDirs, ignorePatterns, title, watch }) => {
     clearTerminal()
     colourLog.title(`${emoji} ${title} ${emoji}`)
     console.log()
@@ -117,7 +121,17 @@ program
       ignoreDirs,
       ignorePatterns,
     })
-    runLintPilot({ cache, filePatterns, fix, title, watch })
+
+    const lintPilotOptions = {
+      cache,
+      eslintUseLegacyConfig,
+      filePatterns,
+      fix,
+      title,
+      watch,
+    }
+
+    runLintPilot(lintPilotOptions)
 
     if (watch) {
       watchFiles({
@@ -129,7 +143,7 @@ program
         clearTerminal()
         colourLog.info(message)
         console.log()
-        runLintPilot({ cache, filePatterns, fix, title, watch })
+        runLintPilot(lintPilotOptions)
       })
     }
   })