ngx-planet

A powerful, reliable, fully-featured and production ready Micro Frontend library for Angular.

APIs consistent with angular style, currently only supports Angular, other frameworks are not supported.

Features

Rendering multiple applications at the same time
Support two mode, coexist and default that switch to another app and destroy active apps
Support application preload
Support style isolation
Built-in communication between multiple applications
Cross application component rendering
Comprehensive examples include routing configuration, lazy loading and all features

Alternatives

single-spa: A javascript front-end framework supports any frameworks.
mooa: A independent-deployment micro-frontend Framework for Angular from single-spa, planet is very similar to it, but planet is more powerful, reliable, productively and more angular.

Installation

$ npm i @worktile/planet --save
// or
$ yarn add @worktile/planet

Dependencies

@angular/cdk, you should install @angular/cdk

Demo

Try out our live demo

Usage

1. Loading NgxPlanetModule in the portal's AppModule

import { NgxPlanetModule } from '@worktile/planet';

@NgModule({
  imports: [
    CommonModule,
    NgxPlanetModule
  ]
})
class AppModule {}

2. Register applications to planet use PlanetService in portal app

@Component({
    selector: 'app-portal-root',
    template: `
<nav>
    <a [routerLink]="['/app1']" routerLinkActive="active">应用1</a>
    <a [routerLink]="['/app2']" routerLinkActive="active">应用2</a>
</nav>
<router-outlet></router-outlet>
<div id="app-host-container"></div>
<div *ngIf="!loadingDone">加载中...</div>
    `
})
export class AppComponent implements OnInit {
    title = 'ngx-planet';

    get loadingDone() {
        return this.planet.loadingDone;
    }

    constructor(
        private planet: Planet
    ) {}

    ngOnInit() {
        this.planet.setOptions({
            switchMode: SwitchModes.coexist,
            errorHandler: error => {
                console.error(`Failed to load resource, error:`, error);
            }
        });

        this.planet.registerApps([
            {
                name: 'app1',
                hostParent: '#app-host-container',
                hostClass: 'thy-layout',
                routerPathPrefix: '/app1',
                resourcePathPrefix: '/static/app1',
                preload: true,
                scripts: [
                    'main.js'
                ],
                styles: [
                    'styles.css'
                ]
            },
            {
                name: 'app2',
                hostParent: '#app-host-container',
                hostClass: 'thy-layout',
                routerPathPrefix: '/app2',
                preload: true,
                scripts: [
                    '/static/app2/main.js'
                ],
                styles: [
                    '/static/app2/styles.css'
                ]
            }
        ]);

        // start monitor route changes
        // get apps to active by current path
        // load static resources which contains javascript and css
        // bootstrap angular sub app module and show it
        this.planet.start();
    }
}

3. Sub App define how to bootstrap AppModule

defineApplication('app1', {
    template: `<app1-root class="app1-root"></app1-root>`,
    bootstrap: (portalApp: PlanetPortalApplication) => {
        return platformBrowserDynamic([
            {
                provide: PlanetPortalApplication,
                useValue: portalApp
            },
            {
                provide: AppRootContext,
                useValue: portalApp.data.appRootContext
            }
        ])
            .bootstrapModule(AppModule)
            .then(appModule => {
                return appModule;
            })
            .catch(error => {
                console.error(error);
                return null;
            });
    }
});

Documents

Sub app configurations

Name	Type	Description	中文描述
name	string	Application's name	子应用的名字
routerPathPrefix	string	Application route path prefix	子应用路由路径前缀，根据这个匹配应用
selector	string	selector of app root component	子应用的启动组件选择器，因为子应用是主应用动态加载的，所以主应用需要先创建这个选择器节点，再启动 AppModule
scripts	string[]	javascript static resource paths	JS 静态资源文件访问地址
styles	string[]	style static resource paths	样式静态资源文件访问地址
resourcePathPrefix	string	path prefix of scripts and styles	脚本和样式文件路径前缀，多个脚本可以避免重复写同样的前缀
hostParent	string or HTMLElement	parent element for render	应用渲染的容器元素, 指定子应用显示在哪个元素内部
hostClass	string	added class for host which is selector	宿主元素的 Class，也就是在子应用启动组件上追加的样式
switchMode	default or coexist	it will be destroyed when set to default, it only hide app when set to coexist	切换子应用的模式，默认切换会销毁，设置 coexist 后只会隐藏
preload	boolean	start preload or not	是否启用预加载，启动后刷新页面等当前页面的应用渲染完毕后预加载子应用
loadSerial	boolean	serial load scripts	是否串行加载脚本静态资源
manifest	string	manifest json file path	manifest.json 文件路径地址，当设置了路径后会先加载这个文件，然后根据 scripts 和 styles 文件名去找到匹配的文件，因为生产环境的静态资文件是 hash 之后的命名，需要动态获取

Communication between applications use GlobalEventDispatcher

import { GlobalEventDispatcher } from "@worktile/planet";

// app1 root module
export class AppModule {
    constructor(private globalEventDispatcher: GlobalEventDispatcher) {
        this.globalEventDispatcher.register('open-a-detail').subscribe(event => {
            // dialog.open(App1DetailComponent);
        });
    }
}

// in other apps
export class OneComponent {
    constructor(private globalEventDispatcher: GlobalEventDispatcher) {
    }

    openDetail() {
        this.globalEventDispatcher.dispatch('open-a-detail', payload);
    }
}

Cross application component rendering

import { PlanetComponentLoader } from "@worktile/planet";

// in app1
export class AppModule {
    constructor(private planetComponentLoader: PlanetComponentLoader) {
        this.planetComponentLoader.register([{ name: 'app1-project-list', component: App1ProjectListComponent }]);
    }
}

// in other apps
export class OneComponent {
    constructor(private planetComponentLoader: PlanetComponentLoader) {
    }

    openDetail() {
        this.planetComponentLoader.load('app1', 'app1-project-list', {
            container: this.containerElementRef,
            initialState: {}
        });
    }
}

FAQ

infinite loop load portal app's js

Because the portal app and sub app are packaged through webpack, there will be conflicts in module dependent files, we should set up additional config runtimeChunk through @angular-builders/custom-webpack, we expect webpack 5 to support micro frontend better.

// extra-webpack.config.js
{    
    optimization: {
        runtimeChunk: false
    }
};

throw error `Cannot read property 'call' of undefined at __webpack_require__ (bootstrap:79)`

Similar to the reasons above, we should set vendorChunk as false for build and serve in angular.json

 ...
 "build": {
    "builder": "@angular-builders/custom-webpack:browser",
    "options": {
          "customWebpackConfig": {
              "path": "./examples/app2/extra-webpack.config.js",
              "mergeStrategies": {
                "module.rules": "prepend"
              },
              "replaceDuplicatePlugins": true
          },
          ...
          "vendorChunk": false,
          ...
      },
  },
  "serve": {
      "builder": "@angular-builders/custom-webpack:dev-server",
      "options": {
          ...
          "vendorChunk": false
          ...
      }
  }
...

throw error `An accessor cannot be declared in an ambient context.`

this is TypeScript's issue, details see an-accessor-cannot-be-declared should setting skipLibCheck as true

"compilerOptions": {
    "skipLibCheck": true
}

Production env throw error `Cannot read property 'call' of undefined` use router lazy load

In webpack 4 multiple webpack runtimes could conflict on the same HTML page, because they use the same global variable for chunk loading. To fix that it was needed to provide a custom name to the output.jsonpFunction configuration, details see Automatic unique naming.

you should set a unique name for each sub application in extra-webpack.config.js

output: { jsonpFunction: "app1" }

Development

npm run start // open http://localhost:3000

or

npm run serve:portal // 3000
npm run serve:app1 // 3001
npm run serve:app2 // 3002

// test
npm run test