https://juejin.im/post/5a6941e1f265da3e33048429
https://juejin.im/post/5c46cbaee51d453f45612a2c
https://juejin.im/post/5c931c4a6fb9a070dc28923b
https://juejin.im/post/5d722e8b6fb9a06ae37283d8#heading-17

webpack 做性能优化

1. 构建速度
   happypack，paraelly-uglify-plugin

2. 压缩

3. 按需加载
   https://juejin.im/post/5a63f082f265da3e303c95cc

4. tree shaking

5. 自定义loader
   https://juejin.im/post/5a5c18f2518825734f52ad65