feat: upgrade to eslint v9 (#1234)

Co-authored-by: GitHub Action <[email protected]>

.github/workflows/test.yml

@@ -37,12 +37,16 @@ jobs:
         run: |
           yarn install
 
-      - name: Run eslint on changed files
+      - name: Run ESLint on changed files
         uses: tj-actions/eslint-changed-files@v25
         with:
           token: ${{ secrets.PAT_TOKEN }}
-          config_path: ".eslintrc.json"
-          ignore_path: ".eslintignore"
+          ignore_patterns: |
+            dist/**
+            lib/**
+            node_modules/**
+            jest.config.js
+            coverage/**
 
       - name: Run build and test
         run: |

eslint.config.mjs

@@ -0,0 +1,44 @@
+import globals from 'globals'
+
+import path from 'path'
+import {fileURLToPath} from 'url'
+import {FlatCompat} from '@eslint/eslintrc'
+import pluginJs from '@eslint/js'
+import prettierConfig from 'eslint-config-prettier'
+import eslintPluginPrettierRecommended from 'eslint-plugin-prettier/recommended'
+
+
+// mimic CommonJS variables -- not needed if using CommonJS
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = path.dirname(__filename)
+const compat = new FlatCompat({ baseDirectory: __dirname, recommendedConfig: pluginJs.configs.recommended })
+
+export default [
+  { languageOptions: { globals: globals.browser }},
+  {
+    ignores: [
+      'dist/**',
+      'lib/**',
+      'node_modules/**',
+      'jest.config.js',
+      'coverage/**'
+    ]
+  },
+  ...compat.extends("standard-with-typescript").map((config) => ({
+    ...config,
+    files: ["**/*.tsx", "**/*.ts"],
+    rules: {
+      ...config.rules,
+      "@typescript-eslint/semi": ["error", "always"],
+      "@typescript-eslint/explicit-function-return-type": "off",
+      "@typescript-eslint/no-floating-promises": "off",
+      "@typescript-eslint/no-non-null-assertion": "off",
+      "@typescript-eslint/strict-boolean-expressions": "off",
+      "@typescript-eslint/ban-ts-comment": "off",
+      "@typescript-eslint/prefer-ts-expect-error": "off",
+      "no-import-assign": "off",
+    },
+  })),
+  prettierConfig, // Turns off all ESLint rules that have the potential to interfere with Prettier rules.
+  eslintPluginPrettierRecommended,
+]

jest.config.js

@@ -3,7 +3,7 @@ module.exports = {
   moduleFileExtensions: ['js', 'ts'],
   testMatch: ['**/*.test.ts'],
   transform: {
-    '^.+\\.ts$': 'ts-jest'
+    '^.+\\.(ts|tsx)$': 'ts-jest',
   },
   verbose: true,
   testTimeout: 10000,

package.json

@@ -39,20 +39,30 @@
     "uuid": "9.0.1"
   },
   "devDependencies": {
-    "@types/jest": "29.5.12",
+    "@eslint/eslintrc": "^3.0.2",
+    "@eslint/js": "^9.1.1",
+    "@types/jest": "^29.5.12",
     "@types/node": "20.12.8",
     "@types/uuid": "9.0.8",
     "@typescript-eslint/eslint-plugin": "7.8.0",
-    "@typescript-eslint/parser": "7.8.0",
     "@vercel/ncc": "0.38.1",
-    "eslint": "8.57.0",
+    "eslint": "^9.1.1",
     "eslint-config-prettier": "^9.0.0",
+    "eslint-config-standard-with-typescript": "^43.0.1",
+    "eslint-plugin-eslint-comments": "^3.2.0",
+    "eslint-plugin-filenames": "^1.3.2",
     "eslint-plugin-github": "4.10.2",
+    "eslint-plugin-i18n-text": "^1.0.1",
+    "eslint-plugin-import": "^2.25.2",
     "eslint-plugin-jest": "28.5.0",
+    "eslint-plugin-n": "^15.0.0 || ^16.0.0 ",
+    "eslint-plugin-no-only-tests": "^3.1.0",
     "eslint-plugin-prettier": "^5.0.0-alpha.2",
+    "eslint-plugin-promise": "^6.0.0",
+    "globals": "^15.0.0",
     "jest": "29.7.0",
     "prettier": "3.2.5",
-    "ts-jest": "29.1.2",
-    "typescript": "5.4.5"
+    "ts-jest": "^29.1.2",
+    "typescript": "<5.4.0"
   }
 }

src/__tests__/main.test.ts

@@ -23,7 +23,7 @@ const defaultEnv = {
   'INPUT_FILES-FROM-SOURCE-FILE': ''
 }
 
-function mockedEnv(testEnvVars: {[key: string]: string}): void {
+function mockedEnv(testEnvVars: Record<string, string>): void {
   jest.replaceProperty(process, 'env', {...process.env, ...testEnvVars})
 }
 
@@ -214,6 +214,7 @@ test('returns the paths of the all other files (input files)', async () => {
   const EXPECTED_FILENAMES = [
     'LICENSE',
     'action.yml',
+    'eslint.config.mjs',
     'jest.config.js',
     'package.json',
     'renovate.json',