webpack5模块联邦

WHAT（Module Federation 是什么？）

Module Federation [ˌfedəˈreɪʃn] 使 JavaScript 应用得以在客户端或服务器上动态运行另一个 bundle 的代码。

这其中的关键点是：动态，包含两个含义：

1、按需，可以把一个包拆开来加载其中一部分；

2、运行时，跑在浏览器而非 node 编译时；

另一个 bundle 的代码，之前应用之间做共享是在文件级或 npm 包级 export 成员，现在可以在应用级 export 成员属性。

Module Federation 里有两个主要概念 host 和 remote。每个项目可以是 host 也可以是 remote，也可以两个都是。

配置 remote

webpack.config.js

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const ModuleFederationPlugin = require("webpack/lib/container/ModuleFederationPlugin");

module.exports = {
  mode: "development",
  entry: "./src/index.js",
  cache: {
    type: "filesystem",
    cacheDirectory: path.resolve(__dirname, "node_modules/.cache/webpack"),
  },
  output: {
    filename: "bundle.js",
    path: path.resolve(__dirname, "dist"),
    publicPath: "http://localhost:8000/",
  },
  devServer: {
    port: 8000,
  },
  optimization: {
    usedExports: true,
  },
  devtool: false,
  module: {
    rules: [
      {
        test: /\.js$/,
        use: [
          {
            loader: "babel-loader",
            options: {
              presets: ["@babel/preset-react"],
            },
          },
        ],
        exclude: /node_modules/,
      },
      {
        test: /\.png$/,
        type: "asset/resource",
      },
      {
        test: /\.css$/,
        use: ["style-loader", "css-loader"],
      },
    ],
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: "./public/index.html",
    }),
    new ModuleFederationPlugin({ // 这里是重点部分
      filename: "remoteEntry.js",
      name: "remote",
      exposes: {
        "./NewsList": "./src/NewsList",
      },
    }),
  ],
};

src/index.js

import("./bootstrap");

src/bootstrap.js

import React from "react";
import ReactDOM from "react-dom";
import App from "./App";
ReactDOM.render(<App />, document.getElementById("root"));

src/App.js

import React from "react";
import NewsList from './NewsList';
const App = () => (
  <div>
    <h2>本地组件NewsList</h2>
    <NewsList />
  </div>
);

export default App;

src/NewsList.js 这个组件导出给别人使用，在 webpack 配置中可以看到。

import React from "react";
export default ()=>(
    <div>新闻列表</div>
)

配置 host

webpack.config.js

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const ModuleFederationPlugin = require("webpack/lib/container/ModuleFederationPlugin");

module.exports = {
  mode: "development",
  entry: "./src/index.js",
  cache: {
    type: "filesystem",
    cacheDirectory: path.resolve(__dirname, "node_modules/.cache/webpack"),
  },
  output: {
    filename: "bundle.js",
    path: path.resolve(__dirname, "dist"),
    publicPath: "http://localhost:9000/",
  },
  devServer: {
    contentBase: path.join(__dirname, 'dist'),
    compress: true,
    port: 9000,
  },
  optimization: {
    usedExports: true,
  },
  devtool: false,
  module: {
    rules: [
      {
        test: /\.js$/,
        use: [
          {
            loader: "babel-loader",
            options: {
              presets: ["@babel/preset-react"],
            },
          },
        ],
        exclude: /node_modules/,
      },
      {
        test: /\.png$/,
        type: "asset/resource",
      },
      {
        test: /\.css$/,
        use: ["style-loader", "css-loader"],
      },
    ],
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: "./public/index.html",
    }),
    new ModuleFederationPlugin({ // 这里是重点部分
      filename: "remoteEntry.js",
      name: "host",
      remotes: {
        remote: "remote@http://localhost:8000/remoteEntry.js"
      }
    })
  ],
};

src/index.js

import("./bootstrap");

src/bootstrap.js

import React from "react";
import ReactDOM from "react-dom";
import App from "./App";
ReactDOM.render(<App />, document.getElementById("root"));

src/App.js 中导入了之前别人写好的 NewsList 组件，在 webpack 配置中可以看到。

import React from "react";
const RemoteNewsList = React.lazy(() => import("remote/NewsList"));

const App = () => (
  <div>
    <h2 >远程组件NewsList</h2>
    <React.Suspense fallback="Loading NewsList">
      <RemoteNewsList />
    </React.Suspense>
  </div>
);
export default App;

A 应用可以引用 B 整个应用，也可以应用 B 的页面和组件。这样一来，灵活性就非常大了。

配置参数

以上代码都可以在我的demo中看到：https://github.com/wuxianqiang/webacpk5-remote