Multiple Async Operations in parallel using Promises and Observables

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <title>angular2 playground</title>
    <link rel="stylesheet" href="style.css" />
    <script src="https://unpkg.com/zone.js/dist/zone.js"></script>
    <script src="https://unpkg.com/zone.js/dist/long-stack-trace-zone.js"></script>
    <script src="https://unpkg.com/reflect-metadata@0.1.3/Reflect.js"></script>
    <script src="https://unpkg.com/systemjs@0.19.31/dist/system.js"></script>
    <script src="config.js"></script>
    <script>
    System.import('app')
      .catch(console.error.bind(console));
  </script>
  </head>

  <body>
    <my-app>
    loading...
  </my-app>
  </body>

</html>

/* Styles go here */

### Angular Starter Plunker - Typescript

System.config({
  //use typescript for compilation
  transpiler: 'typescript',
  //typescript compiler options
  typescriptOptions: {
    emitDecoratorMetadata: true
  },
  paths: {
    'npm:': 'https://unpkg.com/'
  },
  //map tells the System loader where to look for things
  map: {
    
    'app': './src',
    
    '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
    '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
    '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
    '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
    '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
    '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
    '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
    '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
    
    '@angular/core/testing': 'npm:@angular/core/bundles/core-testing.umd.js',
    '@angular/common/testing': 'npm:@angular/common/bundles/common-testing.umd.js',
    '@angular/compiler/testing': 'npm:@angular/compiler/bundles/compiler-testing.umd.js',
    '@angular/platform-browser/testing': 'npm:@angular/platform-browser/bundles/platform-browser-testing.umd.js',
    '@angular/platform-browser-dynamic/testing': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic-testing.umd.js',
    '@angular/http/testing': 'npm:@angular/http/bundles/http-testing.umd.js',
    '@angular/router/testing': 'npm:@angular/router/bundles/router-testing.umd.js',
    
    'rxjs': 'npm:rxjs',
    'typescript': 'npm:typescript@2.0.2/lib/typescript.js'
  },
  //packages defines our app package
  packages: {
    app: {
      main: './main.ts',
      defaultExtension: 'ts'
    },
    rxjs: {
      defaultExtension: 'js'
    }
  }
});

//main entry point
import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
import {AppModule} from './app';

platformBrowserDynamic().bootstrapModule(AppModule)

//our root app component
import {Component, NgModule} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import {Observable} from 'rxjs/Rx';

@Component({
  selector: 'my-app',
  template: `
    <div>
      <h1>Multiple Asynchronous Operations in Parallel</h1>
      <hr />
      <div>
        <h3>Promises</h3>
        <div>Random # from first Promise: {{promiseRandResult1}}</div>
        <div>Random # from first Promise: {{promiseRandResult2}}</div>
        <div>Random # from first Promise: {{promiseRandResult3}}</div>
        <div>All Promises Status: {{allPromisesStatus}}</div>
        <input type="button" [disabled]="allPromisesStatus === 'Running'" value="Trigger" (click)="doMultipleAsnycOperationsWithPromises()" />
      </div>
      <hr />
      <div>
        <h3>Observables</h3>
        <div>Random # from first Observable: {{observableRandResult1}}</div>
        <div>Random # from first Observable: {{observableRandResult2}}</div>
        <div>Random # from first Observable: {{observableRandResult3}}</div>
        <div>All Observables Status: {{allObservablesStatus}}</div>
        <input type="button" [disabled]="allObservablesStatus === 'Running'" value="Trigger" (click)="doMultipleAsnycOperationsWithObservables()" />
      </div>
    </div>
  `,
})
export class App {
  public promiseRandResult1: number = 0;
  public promiseRandResult2: number = 0;
  public promiseRandResult3: number = 0;
  public allPromisesStatus: string = "Idle";
  public observableRandResult1: number = 0;
  public observableRandResult2: number = 0;
  public observableRandResult3: number = 0;
  public allObservablesStatus: string = "Idle";
  constructor() {
  }
  
  public doMultipleAsnycOperationsWithPromises(): void {
    this.promiseRandResult1 = 0;
    this.promiseRandResult2 = 0;
    this.promiseRandResult3 = 0;
    this.allPromisesStatus = "Running";
    
    this._multiplePromisesWorkerAsync().then((result) => {
      this.allPromisesStatus = "Idle";
    });
  }
  
  public doMultipleAsnycOperationsWithObservables(): void {
    this.observableRandResult1 = 0;
    this.observableRandResult2 = 0;
    this.observableRandResult3 = 0;
    this.allObservablesStatus = "Running";
    
    this._multipleObservablesWorkerAsync().subscribe((result) => {
      this.allObservablesStatus = "Idle";
    });
  }
  
  private _multiplePromisesWorkerAsync(): Promise {
    let promises: Promise[] = [];
    
    promises.push(new Promise<any>(resolve => setTimeout(resolve, 1000))
      .then(() => { return Promise.resolve((Math.random() * 100).toFixed(0)); })
      .then((randNum) => this.promiseRandResult1 = randNum));
    
    promises.push(new Promise<any>(resolve => setTimeout(resolve, 2000))
      .then(() => { return Promise.resolve((Math.random() * 100).toFixed(0)); })
      .then((randNum) => this.promiseRandResult2 = randNum));
    
    promises.push(new Promise<any>(resolve => setTimeout(resolve, 3000))
      .then(() => { return Promise.resolve((Math.random() * 100).toFixed(0)); })
      .then((randNum) => this.promiseRandResult3 = randNum));
    
    return Promise.all(promises);
  }
  
  private _multipleObservablesWorkerAsync(): Observable {
    let observables: Observable[] = [];
    
    observables.push(new Observable(observer => {
      setTimeout(() => {
        observer.next((Math.random() * 100).toFixed(0));
        observer.complete();
      }, 1000);
    }).do((randNum) => {
      this.observableRandResult1 = randNum;
    }));
    
    observables.push(new Observable(observer => {
      setTimeout(() => {
        observer.next((Math.random() * 100).toFixed(0));
        observer.complete();
      }, 2000);
    }).do((randNum) => {
      this.observableRandResult2 = randNum;
    }));
    
    observables.push(new Observable(observer => {
      setTimeout(() => {
        observer.next((Math.random() * 100).toFixed(0));
        observer.complete();
      }, 3000);
    }).do((randNum) => {
      this.observableRandResult3 = randNum;
    }));
    
    return Observable.forkJoin(observables);
  }
}

@NgModule({
  imports: [ BrowserModule ],
  declarations: [ App ],
  bootstrap: [ App ]
})
export class AppModule {}