feat: add eslint

Author: Hedwig-Fang

.eslintrc.js

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