docs: enable contextIsolation in fiddles (#39613)

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

@@ -83,9 +83,6 @@ ipcMain.on('save-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/save-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')
     }
   })
 
@@ -59,14 +59,12 @@ app.on('activate', function () {
   }
 })
 
-ipcMain.on('save-dialog', event => {
+ipcMain.handle('save-dialog', async () => {
   const options = {
     title: 'Save an Image',
     filters: [{ name: 'Images', extensions: ['jpg', 'png', 'gif'] }]
   }
-  dialog.showSaveDialog(options, filename => {
-    event.sender.send('saved-file', filename)
-  })
+  return (await dialog.showSaveDialog(options)).filePath
 })
 
 // In this file you can include the rest of your app's specific main process

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

@@ -0,0 +1,5 @@
+const { contextBridge, ipcRenderer } = require('electron/renderer')
+
+contextBridge.exposeInMainWorld('electronAPI', {
+  saveDialog: () => ipcRenderer.invoke('save-dialog')
+})

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

@@ -1,12 +1,6 @@
-const { ipcRenderer } = require('electron/renderer')
-
 const saveBtn = document.getElementById('save-dialog')
 
-saveBtn.addEventListener('click', event => {
-  ipcRenderer.send('save-dialog')
-})
-
-ipcRenderer.on('saved-file', (event, path) => {
-  if (!path) path = 'No path'
+saveBtn.addEventListener('click', async () => {
+  const path = await window.electronAPI.saveDialog()
   document.getElementById('file-saved').innerHTML = `Path selected: ${path}`
 })