main: add context bridge communication example via preload script, set nodeIntegration to false by default, improve security

src/preload/index.ts

@@ -1,5 +1,19 @@
-const main = (): void => {
-  console.log('[Preload] Script loaded.')
-}
+import { contextBridge, ipcRenderer, shell } from 'electron'
 
-main()
+// Whitelist of valid channels used for IPC communication (Send message from Renderer to Main)
+const mainAvailChannels = ['msgRequestGetVersion']
+const rendererAvailChannels = ['msgReceivedVersion']
+
+contextBridge.exposeInMainWorld('mainApi', {
+  openExternal: async (url) => await shell.openExternal(url),
+  send: (channel, data) => {
+    if (mainAvailChannels.includes(channel)) {
+      ipcRenderer.send(channel, data)
+    }
+  },
+  receive: (channel, cbFunc) => {
+    if (rendererAvailChannels.includes(channel)) {
+      ipcRenderer.on(channel, (event, ...args) => cbFunc(...args))
+    }
+  }
+})