Angular async pipe sharing demo

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <title>angular playground</title>
    <link rel="stylesheet" href="style.css" />
    <script src="https://unpkg.com/core-js@2.4.1/client/shim.min.js"></script>
    <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 angular...
    </my-app>
  </body>

</html>

/* Styles go here */

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/animations': 'npm:@angular/animations/bundles/animations.umd.js',
    '@angular/platform-browser/animations': 'npm:@angular/platform-browser/bundles/platform-browser-animations.umd.js',
    '@angular/animations/browser': 'npm:@angular/animations/bundles/animations-browser.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@2.2.1/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, VERSION} from '@angular/core'
import { HttpModule } from '@angular/http';
import {BrowserModule} from '@angular/platform-browser'
import {PersonViewComponent} from './person-view.component';
import {PersonService} from './person.service';

@Component({
  selector: 'my-app',
  template: `
    <div>
      <person-view></person-view>
    </div>
  `,
})
export class App {
}

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

export class Person {
  constructor(public first: string, public last: string) {}
}

import {Injectable} from '@angular/core';
import {Http} from '@angular/http';
import {Person} from 'person.ts';
import 'rxjs/add/operator/do';
import 'rxjs/add/operator/delay';
import 'rxjs/add/operator/map';

@Injectable()
export class PersonService {
  
  constructor(private http: Http) {}
  
  public getAPerson() {
    return this.http.get('https://jsonplaceholder.typicode.com/users/1')
      .do(__ => console.log('Made an HTTP request...'))
      // Make this take a couple seconds so there's a delay.
      .delay(2000)
      .map(request => request.json())
      .map(json => new Person(json.name.split(' ')[0], json.name.split(' ')[1]));
  }
  
}

import {Component, OnInit} from '@angular/core';
import {PersonService} from './person.service';
import {Person} from './person';
import {Observable} from 'rxjs/Observable';

import 'rxjs/add/operator/share';
import 'rxjs/add/operator/shareReplay';
import 'rxjs/add/operator/publishReplay';

@Component({
  selector: 'person-view',
  templateUrl: 'src/person-view.component.htm'
})
export class PersonViewComponent /*implements OnInit*/ {
  
  private person$: Observable<Person>;
  
  constructor(private personService: PersonService) {}
  
  ngOnInit() {
    this.person$ = this.personService
      .getAPerson()
      
      // This one will cause a double-tap on the server
      // .share();
      
      // this one will work as expected
      // .publishReplay(1)
      // .refCount();
      
      // This is the same as the previous one, just using the
      // helpful shareReplay operator
      .shareReplay(1);
  }
  
}

<div *ngIf="!((person$ | async)?.first)">Loading a person...</div>
<div *ngIf="(person$ | async)?.first">
  <div>First Name: {{(person$ | async)?.first}}</div>
  <div>Last Name: {{(person$ | async)?.last}}</div>
</div>