// Ensure fetch works from isolated world origin fetch('http://localhost:1234') fetch('https://localhost:1234') fetch(`file://${__filename}`) 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 }, pageContext: event.data }) })