在实际开发项目时，webpack 生产环境和开发环境的打包有所不同，比如清除打包文件夹和复制文件只应该在生产环境打包时发挥作用。常常使用多配置文件来解决问题。

配置文件目录

// paths.js
const path = require('path')
const appDir = process.cwd()
const resolveApp = (relativePath) => {
  return path.resolve(appDir, relativePath)
}
module.exports = resolveApp

通用配置文件

const resolveApp = require('./paths')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const { merge } = require('webpack-merge')
const ProdConfig = require('./webpack.prod')
const DevConfig = require('./webpack.dev')
const commonConfig = {
  entry: './src/index.js',
  output: {
    filename: 'js/main.js',
    path: resolveApp('./dist')
  },
  resolve: {
    extensions: ['.js', '.json', '.vue', '.jsx'],
    alias: {
      '@': resolveApp('./src')
    }
  },
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          'style-loader',
          {
            loader: 'css-loader',
            options: {
              importLoaders: 1,
              esModule: false
            }
          },
          'postcss-loader'
        ]
      },
      {
        test: /\.less$/,
        use: [
          'style-loader',
          'css-loader',
          'postcss-loader',
          'less-loader'
        ]
      },
      {
        test: /\.(png|svg|gif|jpe?g)$/,
        type: 'asset',
        generator: {
          filename: "img/[name].[hash:4][ext]"
        },
        parser: {
          dataUrlCondition: {
            maxSize: 30 * 1024
          }
        }
      },
      {
        test: /\.(ttf|woff2?)$/,
        type: 'asset/resource',
        generator: {
          filename: 'font/[name].[hash:3][ext]'
        }
      },
      {
        test: /\.jsx?$/,
        use: ['babel-loader']
      }
    ]
  },
  plugins: [
    new HtmlWebpackPlugin({
      title: 'copyWebpackPlugin',
      template: './public/index.html'
    }),
  ]
}
module.exports = (env) => {
  const isProduction = env.production
  if (!isProduction) {
    process.env.NODE_ENV = isProduction ? 'production' : 'development'
  }
  const config = isProduction ? ProdConfig : DevConfig
  const mergeConfig = merge(commonConfig, config)
  return mergeConfig
}

生产环境配置文件

const CopyWebpackPlugin = require('copy-webpack-plugin')
const { CleanWebpackPlugin } = require('clean-webpack-plugin')
module.exports = {
  mode: 'production',
  plugins: [
    new CleanWebpackPlugin(),
    new CopyWebpackPlugin({
      patterns: [
        {
          from: 'public',
          globOptions: {
            ignore: ['**/index.html']
          }
        }
      ]
    }),
  ]
}

开发环境配置文件

const ReactRefreshWebpackPlugin = require('@pmmmwh/react-refresh-webpack-plugin')
module.exports = {
  mode: 'development',
  devtool: 'cheap-module-source-map',
  target: 'web',
  devServer: {
    // hot: true,
    hotOnly: true,
    open: false,
    port: 4000,
    compress: false,
    historyApiFallback: true,
    proxy: {
      '/api': {
        target: 'https://api.github.com',
        pathRewrite: { "^/api": "" },
        changeOrigin: true
      }
    }
  },
  plugins: [
    new ReactRefreshWebpackPlugin()
  ]
}

其他配置文件

其他配置文件如 babel 也要根据环境区分。

// babel.config.js
const presets = [
  ['@babel/preset-env'],
  ['@babel/preset-react'],
]
const plugins = []
if (process.env.NODE_ENV === 'development') { // 开发环境才需要使用这个插件
  plugins.push(['react-refresh/babel'])
}
module.exports = {
  presets,
  plugins
}

命令行

多配置文件打包的命令需要加上 —env 参数。

"build2": "webpack --config ./config/webpack.common.js --env production",
"serve2": "webpack serve --config ./config/webpack.common.js --env development"