console.log('index.js加载') // import {mul} from './test' //懒加载 点击按钮时再加载test.js 不会重复加载 document.getElementById("btn").onclick = function(){ //分割代码 webpackPrefetch:true 预加载:提前加载js文件 import(/* webpackChunkName: 'test',webpackPrefetch: true */'./test').then(({mul})=>{ console.log(mul(3,5)) }) }