chore: migrate to eslint 9 (#459)

* chore: migrate to eslint 9

* chore: bump deps

* chore: replace license header script with eslint plugin

* chore(deps): oops include package

* chore: workaround for broken plugin

* chore: downgrade yargs

avoid breaking changes

Author: wjhsf

.eslintrc

@@ -30,12 +30,9 @@ jobs:
             - name: Install dependencies
               run: yarn install --frozen-lockfile
 
-            - name: Check License Headers
-              run: yarn check-license-headers
-
             - name: Check formatting
               run: yarn format:check
-            
+
             - name: Run linter
               run: yarn lint
 

.github/workflows/unit.yml

@@ -0,0 +1,57 @@
+import { defineConfig } from 'eslint/config';
+import js from '@eslint/js';
+import globals from 'globals';
+import header from 'eslint-plugin-header';
+import babelParser from '@babel/eslint-parser';
+
+// Workaround for plugin schema validation failing in eslint v9
+// Ref: https://github.com/Stuk/eslint-plugin-header/issues/57#issuecomment-2378485611
+header.rules.header.meta.schema = false;
+
+export default defineConfig([
+    js.configs.recommended,
+    {
+        languageOptions: {
+            globals: {
+                ...globals.node,
+                ...globals.jest,
+            },
+        },
+        plugins: { header },
+        rules: {
+            'header/header': [
+                'error',
+                'block',
+                [
+                    '',
+                    {
+                        pattern:
+                            '^ \\* Copyright \\(c\\) \\d{4}, ([sS]alesforce.com, inc|Salesforce, Inc)\\.$',
+                        // This copyright text should match the text used in the rollup config
+                        template: ` * Copyright (c) ${new Date().getFullYear()}, Salesforce, Inc.`,
+                    },
+                    ' * All rights reserved.',
+                    ' * SPDX-License-Identifier: MIT',
+                    ' * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT',
+                    ' ',
+                ],
+                1 /* newline after header */,
+            ],
+        },
+    },
+    {
+        files: ['src/lightning-stubs/**'],
+        languageOptions: {
+            globals: { ...globals.browser },
+            sourceType: 'module',
+            // Use babel parser for decorator support
+            parser: babelParser,
+            parserOptions: {
+                requireConfigFile: false,
+                babelOptions: {
+                    plugins: [['@babel/plugin-proposal-decorators', { legacy: true }]],
+                },
+            },
+        },
+    },
+]);

eslint.config.mjs

@@ -23,7 +23,6 @@
     },
     "scripts": {
         "prepare": "husky install",
-        "check-license-headers": "node ./scripts/checkLicenseHeaders.js",
         "lint": "eslint src/ tests/",
         "format": "prettier --write '**/*.{js,json,md,html,css}'",
         "format:check": "prettier --check '**/*.{js,json,md,html,css}'",
@@ -50,17 +49,21 @@
         "yargs": "~17.7.2"
     },
     "devDependencies": {
-        "@babel/core": "^7.26.10",
-        "@babel/eslint-parser": "^7.27.0",
-        "@babel/plugin-proposal-decorators": "^7.25.9",
-        "eslint": "^7.32.0",
+        "@babel/core": "^7.28.4",
+        "@babel/eslint-parser": "^7.28.4",
+        "@babel/plugin-proposal-decorators": "^7.28.0",
+        "@eslint/eslintrc": "^3.3.1",
+        "@eslint/js": "^9.36.0",
+        "eslint": "^9.36.0",
+        "eslint-plugin-header": "^3.1.1",
+        "globals": "^16.4.0",
         "husky": "^9.1.7",
-        "isbinaryfile": "^5.0.4",
+        "isbinaryfile": "^5.0.6",
         "lint-staged": "^16.2.3",
-        "prettier": "^3.3.3"
+        "prettier": "^3.6.2"
     },
     "volta": {
-        "node": "20.12.1",
+        "node": "20.19.5",
         "yarn": "1.22.22"
     },
     "lint-staged": {

package.json

@@ -6,8 +6,6 @@
  */
 'use strict';
 
-/* eslint-disable no-console */
-
 function blue(message) {
     // equivalent to chalk.blue()
     return `\x1B[34m${message}\x1B[39m`;