webpackstudy/24/src/js/index.js

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))
  })
}