const { app, BrowserWindow, ipcMain } = require('electron') let mainWindow = null function createWindow () { const windowOptions = { width: 600, height: 400, title: 'Synchronous Messages', webPreferences: { nodeIntegration: true } } mainWindow = new BrowserWindow(windowOptions) mainWindow.loadFile('index.html') mainWindow.on('closed', () => { mainWindow = null }) } app.on('ready', () => { createWindow() }) ipcMain.on('synchronous-message', (event, arg) => { event.returnValue = 'pong' })