# 路由懒加载 ``` // bad! import Wrapper from '@/layout/components/Wrapper/index.vue' // good! const Wrapper = () => import('@/layout/components/Wrapper/index.vue') ``` 优化前:  优化后:  ## webpack ### 1. productionSourceMap ``` // vue.config.js ``` module.exports = { ... // source map 设置为false以加速生产环境构建 productionSourceMap: isProd ? false : true, } ## externals 和CDN