Add eslint for linting

.editorconfig

@@ -6,3 +6,5 @@ insert_final_newline = true
 charset = utf-8
 indent_style = space
 indent_size = 2
+trim_trailing_whitespace = true
+insert_final_newline = true

.eslintrc.json

+{
+    "env": {
+        "browser": true,
+        "es2021": true
+    },
+    "extends": [
+        "google"
+    ],
+    "parserOptions": {
+        "ecmaVersion": 12,
+        "sourceType": "module"
+    },
+    "rules": {
+    }
+}

.gitlab-ci.yml

@@ -9,6 +9,11 @@ before_script:
   - yarn install
   - export PATH="$HOME/.yarn/bin:$PATH"
 
+lint:
+  stage: test
+  script:
+    - yarn lint
+
 pages:
   stage: deploy
   only:

package.json

@@ -12,9 +12,12 @@
     "phaser": "^3.54.0"
   },
   "scripts": {
-    "build": "webpack"
+    "build": "webpack",
+    "lint": "eslint ./src"
   },
   "devDependencies": {
+    "eslint": "^7.25.0",
+    "eslint-config-google": "^0.14.0",
     "favicons": "^6.2.1",
     "favicons-webpack-plugin": "^5.0.2",
     "html-webpack-plugin": "^5.3.1",