button.onclick = e => import(/ webpackChunkName: “print” , webpackPerfetch: true/ ‘./print’).then(module => {
    var print = module.default;

    print();
    });

    懒加载：/ webpackChunkName: “print” /

    • 当文件需要使用时才加载

    预加载： / webpackPerfetch: true /

    • 会在使用之前，提前加载