update eslint

.eslintrc.js

@@ -0,0 +1,37 @@
+module.exports = {
+  'root': true,
+  'env': {
+    'browser': true,
+    'es2021': true,
+    'node': true,
+    'webextensions': true
+  },
+  'extends': [
+    'eslint:recommended',
+    'plugin:@typescript-eslint/recommended'
+  ],
+  'globals': {
+    'globalThis': false
+  },
+  'overrides': [
+  ],
+  'parser': '@typescript-eslint/parser',
+  'parserOptions': {
+    'ecmaVersion': 'latest'
+  },
+  'plugins': [
+    '@typescript-eslint'
+  ],
+  'rules': {
+    'no-console': 0,
+    'no-unused-vars': ['warn', { 'vars': 'all', 'args': 'after-used' }],
+    'no-undef': ['warn'],
+    'no-proto': ['error'],
+    'prefer-arrow-callback': ['warn'],
+    'prefer-spread': ['warn'],
+    'indent': ['error', 2],
+    'linebreak-style': ['error', 'unix'],
+    'quotes': ['error', 'single'],
+    'semi': ['error', 'always']
+  }
+};

.github/workflows/lint.yml

@@ -0,0 +1,20 @@
+name: lint
+on: [pull_request]
+
+jobs:
+  eslint:
+    name: eslint
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: reviewdog/action-eslint@v1
+        with:
+          reporter: github-pr-review
+          eslint_flags: "."
+          filter_mode: "file"
+          fail_on_error: true

package.json

@@ -4,15 +4,19 @@
   "version": "1.0.0",
   "description": "Example Firefox add-ons created using the WebExtensions API",
   "devDependencies": {
-    "eslint": "^4.4.1"
+    "@typescript-eslint/eslint-plugin": "^5.61.0",
+    "@typescript-eslint/parser": "^5.61.0",
+    "babel-eslint": "^10.1.0",
+    "eslint": "^8.44.0"
   },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/mdn/webextensions-examples.git"
   },
   "scripts": {
     "test": "eslint .",
-    "lint": "eslint ."
+    "lint": "eslint .",
+    "lint:fix": "eslint . --fix"
   },
   "license": "MIT",
   "bugs": {
@@ -25,8 +29,5 @@
     "firefox",
     "mozilla"
   ],
-  "homepage": "https://developer.mozilla.org/Add-ons/WebExtensions/Examples",
-  "dependencies": {
-    "babel-eslint": "^7.2.3"
-  }
+  "homepage": "https://developer.mozilla.org/Add-ons/WebExtensions/Examples"
 }