Angular2 Change Detection Example

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <title>angular2 playground</title>
    <link rel="stylesheet" href="style.css" />
    <script src="https://unpkg.com/zone.js@0.6.21/dist/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="https://unpkg.com/typescript@1.8.10/lib/typescript.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 */

### Angular2 Change Detection Example - Typescript - RC.5

A simple plunker demonstrating how Angular2 change detection is being triggered.

System.config({
  //use typescript for compilation
  transpiler: 'typescript',
  //typescript compiler options
  typescriptOptions: {
    emitDecoratorMetadata: true
  },
  //map tells the System loader where to look for things
  map: {
    app: "./src",
    '@angular': 'https://npmcdn.com/@angular',
    'rxjs': 'https://npmcdn.com/rxjs@5.0.0-beta.6'
  },
  //packages defines our app package
  packages: {
    app: {
      main: './main.ts',
      defaultExtension: 'ts'
    },
    '@angular/core': {
      main: 'bundles/core.umd.js',
      defaultExtension: 'js'
    },
    '@angular/compiler': {
      main: 'bundles/compiler.umd.js',
      defaultExtension: 'js'
    },
    '@angular/common': {
      main: 'bundles/common.umd.js',
      defaultExtension: 'js'
    },
    '@angular/platform-browser-dynamic': {
      main: 'bundles/platform-browser-dynamic.umd.js',
      defaultExtension: 'js'
    },
    '@angular/platform-browser': {
      main: 'bundles/platform-browser.umd.js',
      defaultExtension: 'js'
    },
    '@angular/forms': {
      main: 'index.js',
      defaultExtension: 'js'
    },
    '@angular/router': {
      main: 'index.js',
      defaultExtension: 'js'
    },
    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 {RowComponent} from './row'

@Component({
  selector: 'my-app',
  template: `
    <row *ngFor="let rowData of rows" [data]="rowData"></row>
  `,
  directives: [RowComponent]
})
class App {
  private rows: Array<string> = [];
  
  constructor() {
    for (let i = 0; i < 100; i++) {
      this.rows.push(Math.random().toString(30).substring(2, 10));
    }
    
    setInterval(() => {
      this.rows[parseInt(Math.random()*100, 10)] = '--------';
    }, 2500)
  }
}
}

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

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

@Component({
  selector: 'row',
  template: `
    <pre>{{ rowData }}</pre>
  `,
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class RowComponent {
  @Input() public data: string;
  
  get rowData(): string {
    console.debug('getting row data');
    return this.data;
  }
  
  ngOnChanges(): void {
    console.debug('change');
  }
}