13-环境区分

如何区分开发环境

编写两个不同的配置文件，开发和生成时，分别加载不同的配置文件即可。在不同的配置文件中使用变量来说明环境，也可以通过配置脚本带上–env production来表明开发环境，这样就可以在webpack.config.js中导出的函数中通过参数判断环境，当然最终返回的还是对象。

  "scripts": {
    "build": "webpack --config ./config/webpack.prod.js --env production",
    "serve": "webpack serve --config ./config/webpack.dev.js --env development"
  }

配置分离

先设置process.env.NODE_ENV，然后通过process.env.NODE_ENV获取当前的环境是生产环境还是开发环境。

编写webpack.dev.js和webpack.prod.js及webpack.common.js。然后通过使用merge进行合并。注意babel的配置文件，由于需要判断环境，所以我们在webpack.common.js进行process.env.NODE_ENV的挂载，在babel.config.js拿到进行判断不同环境，babel不同的配置。

webpack.common.js

const resolveApp = require("./paths");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const VueLoaderPlugin = require("vue-loader/lib/plugin");

const { merge } = require("webpack-merge");

const prodConfig = require("./webpack.prod");
const devConfig = require("./webpack.dev");

const commonConfig = {
  entry: "./src/index.js",
  output: {
    filename: "bundle.js",
    path: resolveApp("./build"),
  },
  resolve: {
    extensions: [".wasm", ".mjs", ".js", ".json", ".jsx", ".ts", ".vue"],
    alias: {
      "@": resolveApp("./src"),
      pages: resolveApp("./src/pages"),
    },
  },
  module: {
    rules: [
      {
        test: /\.jsx?$/i,
        use: "babel-loader",
      },
      {
        test: /\.vue$/i,
        use: "vue-loader",
      },
      {
        test: /\.css/i,
        use: ["style-loader", "css-loader"],
      },
    ],
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: "./index.html",
    }),
    new VueLoaderPlugin(),
  ]
};

module.exports = function(env) {
  const isProduction = env.production;
  process.env.NODE_ENV = isProduction ? "production": "development";

  const config = isProduction ? prodConfig : devConfig;
  const mergeConfig = merge(commonConfig, config);

  return mergeConfig;
};

webpack.dev.js

const resolveApp = require('./paths');
const ReactRefreshWebpackPlugin = require('@pmmmwh/react-refresh-webpack-plugin');

const isProduction = false;

console.log("加载devConfig配置文件");

module.exports = {
  mode: "development",
  devServer: {
    hot: true,
    hotOnly: true,
    compress: true,
    contentBase: resolveApp("./why"),
    watchContentBase: true,
    proxy: {
      "/why": {
        target: "http://localhost:8888",
        pathRewrite: {
          "^/why": ""
        },
        secure: false,
        changeOrigin: true
      }
    },
    historyApiFallback: {
      rewrites: [
        {from: /abc/, to: "/index.html"}
      ]
    }
  },
  plugins: [
    // 开发环境
    new ReactRefreshWebpackPlugin(),
  ]
}

webpack.prod.js

const { CleanWebpackPlugin } = require('clean-webpack-plugin');
const isProduction = true;

module.exports = {
  mode: "production",
  plugins: [
    // 生成环境
    new CleanWebpackPlugin({}),
  ]
}