docs: enable contextIsolation in fiddles (#39613)

docs/fiddles/native-ui/dialogs/error-dialog/index.html

@@ -73,9 +73,6 @@ ipcMain.on('open-error-dialog', (event) => {
       </div>
     </div>
 
-    <script>
-      // You can also require other files to run in this process
-      require("./renderer.js");
-    </script>
+    <script src="renderer.js"></script>
   </body>
 </html>

docs/fiddles/native-ui/dialogs/error-dialog/main.js

@@ -1,5 +1,6 @@
 // Modules to control application life and create native browser window
 const { app, BrowserWindow, ipcMain, dialog, shell } = require('electron/main')
+const path = require('node:path')
 
 // Keep a global reference of the window object, if you don't, the window will
 // be closed automatically when the JavaScript object is garbage collected.
@@ -11,8 +12,7 @@ function createWindow () {
     width: 800,
     height: 600,
     webPreferences: {
-      contextIsolation: false,
-      nodeIntegration: true
+      preload: path.join(__dirname, 'preload.js')
     }
   })
 

docs/fiddles/native-ui/dialogs/error-dialog/preload.js

@@ -0,0 +1,5 @@
+const { contextBridge, ipcRenderer } = require('electron/renderer')
+
+contextBridge.exposeInMainWorld('electronAPI', {
+  openErrorDialog: () => ipcRenderer.send('open-error-dialog')
+})

docs/fiddles/native-ui/dialogs/error-dialog/renderer.js

@@ -1,7 +1,5 @@
-const { ipcRenderer } = require('electron/renderer')
-
 const errorBtn = document.getElementById('error-dialog')
 
-errorBtn.addEventListener('click', event => {
-  ipcRenderer.send('open-error-dialog')
+errorBtn.addEventListener('click', () => {
+  window.electronAPI.openErrorDialog()
 })