背景

最近发现项目(基于Vue2)构建比较慢，一次上线发布需要 15 分钟，效率低下。

如今这个时代，时间就是金钱，效率就是生命。

于是这两天抽空对项目做了一次构建优化，线上(多国家)构建时间, 从 10分钟 优化到 4分钟, 本地单次构建时间，从 300秒 优化到 90秒，效果还不错。

今天把 详细的改造过程 和相关 技术原理 整理出来分享给大家，希望对大家有所帮助。

正文

首先看一下摆在面前的问题：

可以明显看出： 整体构建环节耗时过长，效率低下，影响业务的发布和回滚。

线上构建流程：

其中， Build base 和 Build Region 阶段存在优化空间。

Build base 阶段的优化，和运维团队沟通过，后续会增加缓存处理。

本次主要关注 Build Region 阶段。

初步优化后，达到效果如下：

基本达到预期。

下面介绍这次优化的细节。

项目优化实战

面对耗时大这个问题，首先要做耗时数据分析。

这里引入 SpeedMeasurePlugin, 示例代码如下：

# vue.config.js

const SpeedMeasurePlugin = require("speed-measure-webpack-plugin");

configureWebpack: (config) => {
  config.plugins.push(new SpeedMeasurePlugin());
}

得到结果如下：

得到： 

SMP  ⏱  Loaders

cache-loader, and 

vue-loader, and 

eslint-loader took 3 mins, 39.75 secs

  module count = 1894

cache-loader, and 

thread-loader, and 

babel-loader, and 

ts-loader, and 

eslint-loader took 3 mins, 35.23 secs

  module count = 482

cache-loader, and 

thread-loader, and 

babel-loader, and 

ts-loader, and 

cache-loader, and 

vue-loader took 3 mins, 16.98 secs

  module count = 941

cache-loader, and 

vue-loader, and 

cache-loader, and 

vue-loader took 3 mins, 9.005 secs

  module count = 947

mini-css-extract-plugin, and 

css-loader, and 

vue-loader, and 

postcss-loader, and 

sass-loader, and 

cache-loader, and 

vue-loader took 3 mins, 5.29 secs

  module count = 834

modules with no loaders took 1 min, 52.53 secs

  module count = 3258

mini-css-extract-plugin, and 

css-loader, and 

vue-loader, and 

postcss-loader, and 

cache-loader, and 

vue-loader took 27.29 secs

  module count = 25

css-loader, and 

vue-loader, and 

postcss-loader, and 

cache-loader, and 

vue-loader took 27.13 secs

  module count = 25

file-loader took 12.049 secs

  module count = 30

cache-loader, and 

thread-loader, and 

babel-loader took 11.62 secs

  module count = 30

url-loader took 11.51 secs

  module count = 70

mini-css-extract-plugin, and 

css-loader, and 

postcss-loader took 9.66 secs

  module count = 8

cache-loader, and 

thread-loader, and 

babel-loader, and 

ts-loader took 7.56 secs

  module count = 3

css-loader, and 

// ...


Build complete.

fetch translations

en has been saved!

id has been saved!

sp-MX has been saved!

vi has been saved!

zh-TW has been saved!

zh-CN has been saved!

th has been saved!

$ node ./script/copy-static-asset.js

✨  Done in 289.96s.

统计出耗时比较大的几个loader:


Vue-loader 
eslint-loader
babel-loader
Ts-loader,
Thread-loader,
cache-loader

一般而言，代码编译时间和代码规模正相关。

根据以往优化经验，代码静态检查可能会占据比较多时间，目光锁定在 eslint-loader 上。

在生产构建阶段， eslint 提示信息价值不大，考虑在 build 阶段去除，步骤前置。

比如在 commit 的时候做检查，或者在 merge 的时候加一条流水线，专门做静态检查。

给出部分示例代码：

image: harbor.shopeemobile.com/shopee/nodejs-base:16

stages:
  - ci

ci_job:
  stage: ci
  allow_failure: false
  only:
    - merge_requests
  script:
    - npm i -g pnpm
    - pnpm pre-build && pnpm lint && pnpm test
  cache:
    paths:
      - node_modules
    key: project

于此，初步确定两个优化方向:

优化构建流程，在生产构建阶段去除不必要的检查。
集成 esbuild，加快底层构建速度。

1. 优化构建流程

检查项目的配置发现：

# vue.config.js

lintOnSave: true,

修改为：

# vue.config.js

lintOnSave: process.env.NODE_ENV !== 'production',

即：生产环境的构建不做 lint 检查。

Vue 官网对此也有相关描述：cli.vuejs.org/zh/config/#…

再次构建，得到如下数据：

 SMP  ⏱  Loaders
cache-loader, and 
vue-loader took 1 min, 34.33 secs
  module count = 2841
cache-loader, and 
thread-loader, and 
babel-loader, and 
ts-loader took 1 min, 33.56 secs
  module count = 485
vue-loader, and 
cache-loader, and 
thread-loader, and 
babel-loader, and 
ts-loader, and 
cache-loader, and 
vue-loader took 1 min, 31.41 secs
  module count = 1882
vue-loader, and 
mini-css-extract-plugin, and 
css-loader, and 
postcss-loader, and 
sass-loader, and 
cache-loader, and 
vue-loader took 1 min, 29.55 secs
  module count = 1668
css-loader, and 
vue-loader, and 
postcss-loader, and 
sass-loader, and 
cache-loader, and 
vue-loader took 1 min, 27.75 secs
  module count = 834
modules with no loaders took 59.89 secs
  module count = 3258
...

Build complete.
fetch translations
vi has been saved!
zh-TW has been saved!
en has been saved!
th has been saved!
sp-MX has been saved!
zh-CN has been saved!
id has been saved!
$ node ./script/copy-static-asset.js

✨  Done in 160.67s.

有一定提升，其他 loader 耗时数据无明显异常。

下面开始集成 esbuid。

集成 esbuild

这部分的工作，主要是：集成 esbuild 插件到脚手架中。

具体代码的修改，要看具体情况，大体分为两类：

自己用 webpack 实现了打包逻辑。
用的是 cli 自带的打包配置，比如 vue-cli。

这两种方式我都会介绍，虽然形式上有所差异，但是原理都是一样的。

核心思路如下：

rules: [
    {
        test: /\.(js|jsx|ts|tsx)$/,
        loader: 'esbuild-loader',
        options: {
            charset: 'utf8',
            loader: 'tsx',
            target: 'es2015',
            tsconfigRaw: require('../../tsconfig.json'),
        },
        exclude: /node_modules/,
    },
    ...
]

const { ESBuildMinifyPlugin } = require('esbuild-loader');

optimization: {
    minimizer: [
        new ESBuildMinifyPlugin({
            target: 'es2015',
            css: true,
        }),
    ],
    ...
}

具体实现上，简单区分为两类，详细配置如下：

一、webpack.config.js

npm i -D esbuild-loader

1. Javascript & JSX transpilation (eg. Babel)

In webpack.config.js:

  module.exports = {
    module: {
      rules: [
-       {
-         test: /\.js$/,
-         use: 'babel-loader',
-       },
+       {
+         test: /\.js$/,
+         loader: 'esbuild-loader',
+         options: {
+           loader: 'jsx',  // Remove this if you're not using JSX
+           target: 'es2015'  // Syntax to compile to (see options below for possible values)
+         }
+       },

        ...
      ],
    },
  }

2. TypeScript & TSX

In webpack.config.js:

  module.exports = {
    module: {
      rules: [
-       {
-         test: /\.tsx?$/,
-         use: 'ts-loader'
-       },
+       {
+         test: /\.tsx?$/,
+         loader: 'esbuild-loader',
+         options: {
+           loader: 'tsx',  // Or 'ts' if you don't need tsx
+           target: 'es2015',
+		    tsconfigRaw: require('./tsconfig.json'), // If you have a tsconfig.json file, esbuild-loader will automatically detect it.
+         }
+       },

        ...
      ]
    },
  }

3. JS Minification (eg. Terser)

esbuild 在代码压缩上，也有不错的表现：

详细对比数据见：github.com/privatenumb…

In webpack.config.js:

+ const { ESBuildMinifyPlugin } = require('esbuild-loader')

  module.exports = {
    ...,

+   optimization: {
+     minimizer: [
+       new ESBuildMinifyPlugin({
+         target: 'es2015'  // Syntax to compile to (see options below for possible values)
+ 		css: true  // Apply minification to CSS assets
+       })
+     ]
+   },
  }

4. CSS in JS

如果你的 css 样式不导出为 css 文件，而是通过比如'style-loader'加载的，也可以通过esbuild来优化。

In webpack.config.js:


  module.exports = {
    module: {
      rules: [
        {
          test: /\.css$/i,
          use: [
            'style-loader',
            'css-loader',
+           {
+             loader: 'esbuild-loader',
+             options: {
+               loader: 'css',
+               minify: true
+             }
+           }
          ]
        }
      ]
    }
  }

更多 esbuild 案例，可以参考： github.com/privatenumb…

二、vue.config.js

配置比较简单，直接贴代码了：

// vue.config.js

const { ESBuildMinifyPlugin } = require('esbuild-loader');

module.exports = {
  // ...

  chainWebpack: (config) => {
    // 使用 esbuild 编译 js 文件
    const rule = config.module.rule('js');

    // 清理自带的 babel-loader
    rule.uses.clear();

    // 添加 esbuild-loader
    rule
      .use('esbuild-loader')
      .loader('esbuild-loader')
      .options({
        loader: 'ts', // 如果使用了 ts, 或者 vue 的 class 装饰器，则需要加上这个 option 配置， 否则会报错： ERROR: Unexpected "@"
        target: 'es2015',
        tsconfigRaw: require('./tsconfig.json')
      })

    // 删除底层 terser, 换用 esbuild-minimize-plugin
    config.optimization.minimizers.delete('terser');

    // 使用 esbuild 优化 css 压缩
    config.optimization
      .minimizer('esbuild')
      .use(ESBuildMinifyPlugin, [{ minify: true, css: true }]);
  }
}