const { ipcRenderer, webFrame } = require('electron'); window.foo = 3; webFrame.executeJavaScript('window.preloadExecuteJavaScriptProperty = 1234;'); window.addEventListener('message', (event) => { ipcRenderer.send('isolated-world', { preloadContext: { preloadProperty: typeof window.foo, pageProperty: typeof window.hello, typeofRequire: typeof require, typeofProcess: typeof process, typeofArrayPush: typeof Array.prototype.push, typeofFunctionApply: typeof Function.prototype.apply, typeofPreloadExecuteJavaScriptProperty: typeof window.preloadExecuteJavaScriptProperty }, pageContext: event.data }); });