微前端框架single-spa入门

停更已一年多，期间做了很多团队和项目管理的事情。回归初心~

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1. 微前端

如何实现多个应用间的资源共享？

方案一： npm包的抽离和引用

缺点

• 开发及效率问题
  先发布npm包；更新使用了该npm包的应用；项目构建
• 多团队代码管理问题
  不同团队编码风格不同，每引入一个npm包，风格不一致

方案二：微前端

微前端官网：https://micro-frontends.org
定义：

Techniques, strategies and recipes for building a modern web app with multiple teams that can ship features independently.

特点：

• 独立部署
• 增量迁移
• 团队自治
• 松耦合代码

2. single-spa介绍

描述: A javascript router for front-end microservices
官网: https://single-spa.js.org/

3. 安装及项目启动

（1）安装及新建项目并启动

npm i [email protected] -g
create-single-spa

完成后执行npm start，如下图即为成功

（2）错误排查

开始使用[email protected]完成项目create后，执行npm start会报以下错误

[webpack-cli] Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
 - options has an unknown property 'firewall'. These properties are valid:
   object { allowedHosts?, bonjour?, client?, compress?, devMiddleware?, headers?, historyApiFallback?, host?, hot?, http2?, https?, ipc?, liveReload?, onAfterSetupMiddleware?, onBeforeSetupMiddleware?, onListening?, open?, port?, proxy?, setupExitSignals?, static?, watchFiles?, webSocketServer? }
 - options.client has an unknown property 'host'. These properties are valid:
   object { logging?, overlay?, progress?, webSocketTransport?, webSocketURL? }

参考https://github.com/single-spa/create-single-spa/issues/309，版本3.0.2则不会出现上述问题。

4. 配置

The single-spa root config consists of the following:
[1] The root HTML file that is shared by all single-spa applications.
[2] The JavaScript that calls singleSpa.registerApplication().
Your root config exists only to start up the single-spa applications.

（1）引入子应用：study-root-config.js

Register Application的属性说明如下：

• name: String, 微前端应用名称“@组织名称/应用名称 ”
• app: Function,return Promise, 通过systemjs引用打包好的微前端应用模块代码
• activeWhen: 路由匹配时激活应用

import { registerApplication, start } from "single-spa";
registerApplication({
  name: "@single-spa/welcome",
  app: () =>
    System.import(
      "https://unpkg.com/single-spa-welcome/dist/single-spa-welcome.js"
    ),
  activeWhen: ["/"],
});

// registerApplication({
//   name: "@study/navbar",
//   app: () => System.import("@study/navbar"),
//   activeWhen: ["/"]
// });

start({
  urlRerouteOnly: true,
});

（2）Root HTML file：index.ejs

index.ej中引入基座

5. 新建并引入一个Vue的子应用

（1）创建Vue子应用

create-single-spa

注意type此时需选择single-spa application

项目初始化成功后，修改package.json如下，指定启动9001端口。

"serve": "vue-cli-service serve --port 9001",

（2）注册子应用到容器

在container的study-root-config.js中注册：

registerApplication({
  name: "@study/test-vue",
  app: () => System.import("@study/test-vue"),
  activeWhen: ["/test-vue"]
});

（3）增加vue及vue-router引用及子应用挂载

在container的index.ejs中增加vue及vue-router，并增加应用挂载：

{
   "imports": {
     "single-spa": "https://cdn.jsdelivr.net/npm/[email protected]/lib/system/single-spa.min.js",
     "vue": "https://cdn.jsdelivr.net/npm/[email protected]/dist/vue.js",
     "vue-router":"https://cdn.jsdelivr.net/npm/[email protected]/dist/vue-router.min.js"
   }
 }

{
 "imports": {
    "@study/root-config": "//localhost:9000/study-root-config.js",
    "@study/test-vue":"//localhost:9001/js/app.js"
  }
}

（4）增加vue.config.js

在根目录新建vue.config.js代码如下：

module.exports = {
    chainWebpack: config =>{
        //不打包vue及vue-router
        config.externals(["vue","vue-router"])
    }
}

（5）修改注册路由

至此，当访问http://localhost:9000/test-vue依旧不能显示正确的vue工程页面。当把容器的路径由’/‘改为’/welcome’时，vue工程便可以正确显示。

registerApplication({
  name: "@single-spa/welcome",
  app: () =>
    System.import(
      "https://unpkg.com/single-spa-welcome/dist/single-spa-welcome.js"
    ),
  activeWhen: ["/welcome"],

所以，当为’/test-vue’时，’/'也可以匹配。故需要将根路径修改为精确匹配。

registerApplication(
  "@single-spa/welcome",
  () =>
    System.import(
      "https://unpkg.com/single-spa-welcome/dist/single-spa-welcome.js"
    ),
  location => location.pathname === '/'
);

两个路由地址便可以访问不同页面。

（6）Vue内部路由

在子应用的main.js中引入Router，创建component并注册。

import Vue from 'vue';
import singleSpaVue from 'single-spa-vue';

import App from './App.vue';

import VueRouter from 'vue-router';

Vue.use(VueRouter);

//路由组件
const Bar = {template:'
This is the Bar Component
'}
//路由规则
const routes = [
  {path:'/bar', component: Bar}
]
//路由实例
const router = new VueRouter({
  routes,
  mode: 'history',
  base: '/test-vue'
})

Vue.config.productionTip = false;

const vueLifecycles = singleSpaVue({
  Vue,
  appOptions: {
    router, //注册router
    render(h) {
      return h(App, {
        props: {
          // single-spa props are available on the "this" object. Forward them to your component as needed.
          // https://single-spa.js.org/docs/building-applications#lifecyle-props
          // if you uncomment these, remember to add matching prop definitions for them in your App.vue file.
          /*
          name: this.name,
          mountParcel: this.mountParcel,
          singleSpa: this.singleSpa,
          */
        },
      });
    },
  },
});

export const bootstrap = vueLifecycles.bootstrap;
export const mount = vueLifecycles.mount;
export const unmount = vueLifecycles.unmount;

在App.vue中增加router-view及跳转链接：

<template>
  <div id="app">
    <router-link to="/">Go back router-link> |
    <router-link to="/bar">Go to barrouter-link>
    <div>
      <router-view />
    div>
  div>
template>

至此，效果如下：

6. 创建utility实现容器间的通信

（1）创建utility模块

create-single-spa

注意type此时需选择in-browser utility module

项目初始化成功后，修改package.json如下，指定启动9005端口。

"serve": "webpack serve --port 9005",

便可以启动该应用。

Utility在src下的study-tools.js文件中可以暴露方法给其他子应用使用。例如：

// Anything exported from this file is importable by other in-browser modules.
export function publicToolsFunction(appName) {
    return `Imported by ${appName}. Here is the response from Tools`;
}

（2）在子应用中的使用

如何使用上述暴露出来的方法呢？首先需要在主应用container->src>index.ejs中引入tools：

{
 "imports": {
    "@study/root-config": "//localhost:9000/study-root-config.js",
    "@study/test-vue":"//localhost:9001/js/app.js",
    "@study/tools":"//localhost:9005/study-tools.js"
  }
}

注意！末尾项不要如js加上逗号，否则会报如下错误：

在上述子应用test-vue中新建页面进行测试。
新建一个componets文件夹下新建Bar.vue。在main.js中将其引入并注释掉之前的路由组件。

import Bar from './components/Bar'

//路由组件
// const Bar = {template:'
This is the Bar Component
'}

Bar.vue中使用：

<template>
  <div>
    <button @click="getTools">Get Tools</button>
    <p>{{msg}}</p>
 </div>
</template>

<script>
export default {
  name: 'Bar',
  data() { 
    return {
      msg:"This is bar"
    }
  },
  methods:{
    async getTools(){
      try {
        let toolsModule = await window.System.import('@study/tools');
        this.msg = toolsModule.publicToolsFunction('bar');
      } catch (error) {
        alert(error);
      }
    }
  },
 }
</script>

点击按钮后的效果：