update styleling to flat config

eslint.config.mjs

@@ -0,0 +1,48 @@
+import eslint from '@eslint/js';
+import prettier from 'eslint-plugin-prettier/recommended';
+import globals from 'globals';
+
+/** @type {import("eslint").Linter.FlatConfig[]} */
+export default [
+  eslint.configs.recommended,
+  prettier,
+  {
+    files: ['src/**/*.js'],
+    languageOptions: {
+      globals: {
+        YUI: true,
+        ...globals.browser,
+      },
+    },
+  },
+  {
+    files: ['tests/**/*.js'],
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+      },
+    },
+  },
+  {
+    files: ['netlify_functions/**/*.js'],
+    languageOptions: {
+      globals: {
+        ...globals.node,
+      },
+    },
+  },
+  {
+    files: ['**/*.mjs'],
+    languageOptions: {
+      parserOptions: {
+        sourceType: 'module',
+        ecmaVersion: 'latest',
+      },
+      globals: {
+        ...globals.node,
+      },
+    },
+  },
+  { ignores: ['dist/', 'tmp/', '.netlify'] },
+];

jsconfig.json

@@ -0,0 +1,7 @@
+{
+  "compilerOptions": {
+    "module": "ESNext",
+    "target": "ESNext"
+  },
+  "exclude": ["node_modules"]
+}

package.json

@@ -28,12 +28,14 @@
     "test": "playwright test"
   },
   "devDependencies": {
+    "@eslint/js": "9.2.0",
     "@playwright/test": "^1.36.2",
+    "@types/eslint": "^8.56.10",
     "@types/node": "^20.0.0",
-    "eslint": "8.57.0",
+    "eslint": "9.2.0",
     "eslint-config-prettier": "9.1.0",
-    "eslint-plugin-node": "11.1.0",
     "eslint-plugin-prettier": "5.1.3",
+    "globals": "^15.2.0",
     "lefthook": "^1.6.8",
     "mockdate": "^3.0.5",
     "netlify-cli": "17.23.5",