epp/client-entrance-guard/preload.js

// import { remote } from 'electron'

// const setFullScreen = remote.getCurrentWindow().setFullScreen
// const isFullScreen = remote.getCurrentWindow().isFullScreen
// window.setFullScreen = setFullScreen
// window.isFullScreen = isFullScreen

window.addEventListener('DOMContentLoaded', () => {
    // document.getElementById("fullscreen-button").onclick = function () {
    //     alert(1)
    //     window.setFullScreen(!window.isFullScreen)
    // }
})