Develoment 和 Production 模式的区分打包

为什么要区分Develoment 和 Production

Develoment环境需要开启devServer方便开发,Production环境需要精简sourceMap和对代码进行压缩、

方式一：不同模式用不同配置文件打包

1.安装webpack-merge合并多个配置文件

npm install webpack-merge -d

2.webpack-common.js做公共的配置

const path = require('path')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const { CleanWebpackPlugin } = require('clean-webpack-plugin');
module.exports = {
  entry: {
    main: './src/index.js'
  },
  module: {
    rules: [
      {
        test: /.jpg$/,
        use: {
          loader: 'file-loader',
          options: {
            //占位符
            name: "[name].[ext]",
            outputPath: './img',
            limit: 2048
          }
        }
      },
      {
        test: /.scss$/,
        use: [
          'style-loader',
          {
            loader: 'css-loader',
            options: {
              //通过import引入的scss文件，也走下班2个loader
              importLoaders: 2,
              //开启模块化
              modules: true
            }
          },
          'sass-loader',
          'postcss-loader'
        ]
      },
      {
        test: /.css$/,
        use: [
          'style-loader',
          'css-loader',
          'postcss-loader'
        ]
      },
      {
        test: /.js$/,
        exclude: /node_modules/,
        loader: 'babel-loader'
      }
    ]
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: './src/index.html'
    }),
    new CleanWebpackPlugin()
  ],
  output: {
    filename: '[name].js',
    path: path.resolve(__dirname, 'dist')
  }
}

3.webpack-dev.js做的Develoment 环境的配置

const webpack = require('webpack')
const { merge } = require('webpack-merge')
const commonConfig = require('./webpack-common.js')
const devConfig = {
  mode: 'development',
  devtool: 'cheap-module-eval-source-map',
  devServer: {
    contentBase: './dist/',//开启服务器的目录
    open: true,//自动打开一个浏览器，
    hot: true,
    proxy: {
      '/api': 'http://localhost:3000'
    },
  },
  optimization: {
    usedExports: true
  },
  plugins: [
    new webpack.HotModuleReplacementPlugin()
  ],
}
module.exports = merge(commonConfig, devConfig)

4.webpack-prod.js做的Production 环境的配置

const { merge } = require('webpack-merge')
const commonConfig = require('./webpack-common.js')
const prodConfig = {
  mode: 'production',
  devtool: 'cheap-module-source-map',
}
module.exports = merge(commonConfig, prodConfig)

5.pakeage.json 利用不同的打包文件打包

  "scripts": {
    "dev": "webpack-dev-server --config webpack-dev.js",
    "build": "webpack --config webpack-prod.js"
  },
  "sideEffects": [
    "*.css"
  ]

方式二：不同模式用不同的环境变量打包

1.安装webpack-merge合并多个配置文件

npm install webpack-merge -d

3.webpack-dev.js做的Develoment 环境的配置

const webpack = require('webpack')
// const { merge } = require('webpack-merge')
const commonConfig = require('./webpack-common.js')
const devConfig = {
...
}
module.exports = devConfig
// module.exports = merge(commonConfig, devConfig)

4.webpack-prod.js做的Production 环境的配置

// const { merge } = require('webpack-merge')
const commonConfig = require('./webpack-common.js')
const prodConfig = {
  ...
}
// module.exports = merge(commonConfig, prodConfig)
module.exports = prodConfig

2.webpack-common.js做公共的配置,并且根据环境变量，到处不同的merge config

...
const { merge } = require('webpack-merge')
const devConfig = require('./webpack-dev.js')
const prodConfig = require('./webpack-prod.js')
const commonConfig = {
  ...
}
//关键代码
module.exports = function (env) {
  if (env && env.production) {
    return merge(commonConfig, prodConfig)
  } else {
    return merge(commonConfig, devConfig)
  }
}

5.pakeage.json 不再利用不同的打包文件打包

不再利用不同的打包文件打包，而都是webpack-common.js。build的时候传了环境变量--env.production。

"scripts": {
    "dev": "webpack-dev-server --config webpack-common.js",
    "build": "webpack --env.production --config webpack-common.js",
    "dev-build": "webpack --profile --json > stats.json --config webpack-common.js "
  },