Angular ViewChild

<!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/app.module';

platformBrowserDynamic().bootstrapModule(AppModule)

import { NgModule } from '@angular/core'
import { FormsModule } from '@angular/forms'
import { BrowserModule } from '@angular/platform-browser'

import { AppComponent } from './app.component';

import { TestParentComponent } from './test-parent/test-parent.component';
import { TestChildComponent } from './test-parent/test-child/test-child.component';


@NgModule({
  imports: [ BrowserModule, FormsModule ],
  declarations: [ AppComponent, TestParentComponent, TestChildComponent ],
  bootstrap: [ AppComponent ]
})
export class AppModule {}

import { Component, ViewChildren, QueryList } from '@angular/core';
import { TestChildComponent } from './test-child/test-child.component';

@Component({
  selector: 'test-parent',
  template: `
  <ol>
    <li *ngFor="let num of checkListNums">
      <test-child></test-child>
    </li>
  </ol>
  <div>
    <button type="button" (click)="checkedAll()">Check All</button>
    <button type="button" (click)="unCheckedAll()">Uncheck All</button>
  </div>
      `
})
export class TestParentComponent {
  checkListNums: number[];
  @ViewChildren(TestChildComponent) testChild: QueryList<TestChildComponent>;
  
  constructor() {
    this.checkListNums = [1, 2, 3];
  }
  
  checkedAll() {
    this.testChild.map((comp) => comp.isChecked = true);
  }
  
  unCheckedAll() {
    this.testChild.map((comp) => comp.isChecked = false);
  }

}

import { Component, ViewChild } from '@angular/core';

@Component({
  selector: 'test-child',
  template: `
  <label>check me</label><input type="checkbox" [(ngModel)]="isChecked">
  `
})
export class TestChildComponent {
  isChecked: boolean;
  
  constructor() {
    this.isChecked = false;
  }

}

import { Component } from '@angular/core'

@Component({
  selector: 'my-app',
  template: '<test-parent></test-parent>'
})
export class AppComponent {}