Add ESLint configuration and related files; update .gitignore and package.json

.github/workflows/eslint.yml

@@ -0,0 +1,27 @@
+name: ESLint
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+      
+    - name: Setup Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version: '20'
+        cache: 'npm'
+        
+    - name: Install dependencies
+      run: npm ci
+      
+    - name: Run ESLint
+      run: npx eslint . --max-warnings 0

.gitignore

@@ -11,6 +11,8 @@ data/cores/*
 !data/cores/.npmignore
 .DS_Store
 .vscode/*
+!.vscode/settings.json
+!.vscode/extensions.json
 *.tgz
 dist/
 jsdoc/

.vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+    "recommendations": [
+        "dbaeumer.vscode-eslint"
+    ]
+}

.vscode/settings.json

@@ -0,0 +1,8 @@
+{
+    "diffEditor.ignoreTrimWhitespace": false,
+    "editor.formatOnPaste": false,
+    "editor.formatOnSave": false,
+    "editor.formatOnSaveMode": "modifications",
+    "eslint.enable": true,
+    "eslint.lintTask.enable": true
+}

eslint.config.js

@@ -0,0 +1,23 @@
+export default [
+    {
+        files: ["**/*.js"],
+        languageOptions: {
+            ecmaVersion: 2020,
+            sourceType: "module",
+            globals: {
+                console: "readonly",
+                window: "readonly",
+                document: "readonly",
+                navigator: "readonly",
+                fetch: "readonly",
+                localStorage: "readonly",
+                sessionStorage: "readonly"
+            }
+        },
+        rules: {
+            "no-var": "warn",
+            "prefer-const": "warn",
+            "prefer-arrow-callback": "warn"
+        }
+    }
+];

jsconfig.json

@@ -1,6 +1,6 @@
 {
     "compilerOptions": {
         "module": "CommonJS",
-        "target": "ES2022"
+        "target": "ES2020"
     }
 }

package.json

@@ -31,6 +31,7 @@
         "@emulatorjs/cores": "latest"
     },
     "devDependencies": {
+        "eslint": "^9.39.2",
         "jsdoc": "^4.0.4",
         "nipplejs": "^0.10.2",
         "node-fetch": "^3.3.2",