add linter and formatter

.eslintrc.js

@@ -0,0 +1,17 @@
+'use strict';
+module.exports = {
+  extends: ['eslint:recommended', 'eslint-config-prettier'],
+  parserOptions: {
+    ecmaVersion: 2020,
+  },
+  env: {
+    browser: true,
+  },
+  rules: {
+    strict: ['error', 'global'],
+    'no-unused-vars': ['error', { vars: 'local' }],
+    eqeqeq: ['error', 'always', { null: 'ignore' }],
+    curly: ['error', 'multi-line'],
+    'no-var': 'error',
+  },
+};

.gitignore

@@ -3,3 +3,6 @@ extension/manifest.json
 
 # release builds
 release/*
+
+# JavaScript stuff
+node_modules

package.json

@@ -0,0 +1,18 @@
+{
+  "name": "tubearchivist-browser-extension",
+  "private": true,
+  "scripts": {
+    "lint": "eslint 'extension/**/*.js'",
+    "format": "prettier --write 'extension/**/*.js'"
+  },
+  "devDependencies": {
+    "eslint": "^8.26.0",
+    "prettier": "^2.7.1",
+    "eslint-config-prettier": "^8.5.0"
+  },
+  "prettier": {
+    "singleQuote": true,
+    "arrowParens": "avoid",
+    "printWidth": 100
+  }
+}