add eslint

.eslintrc.js

@@ -0,0 +1,26 @@
+module.exports = {
+  env: {
+    browser: true,
+    es2021: true,
+  },
+  extends: 'eslint:recommended',
+  globals: {
+    global: true,
+  },
+  overrides: [
+    {
+      env: {
+        node: true,
+      },
+      files: ['.eslintrc.{js,cjs}'],
+      parserOptions: {
+        sourceType: 'script',
+      },
+    },
+  ],
+  parserOptions: {
+    ecmaVersion: 'latest',
+    sourceType: 'module',
+  },
+  rules: {},
+};

.github/workflows/node.js.yml

@@ -20,6 +20,8 @@ jobs:
           node-version: ${{ matrix.node-version }}
           cache: 'npm'
       - run: npm ci
+      - run: npm run lint
+      - run: npm run format:check
       - run: npm test
   deploy:
     runs-on: ubuntu-latest