main.js

const { app, BrowserWindow } = require('electron')
const path = require('path')
const url = require('url')

let win

function createWindow() {
    win = new BrowserWindow({ width: 800, height: 600 })
    win.loadURL(url.format({
        pathname: path.join(__dirname, 'index.html'),
        protocol: 'file:',
        slashes: true
    })
    )
    win.webContents.openDevTools()
    win.on('closed', () => {
        win = null
    })
}
app.on('ready', createWindow)