angular2关于内置通道的使用

@Component({
  selector: 'slice-list-pipe',
  template: `<ul>
    <li *ngFor="let i of collection | slice:1:3">{{i}}</li>
  </ul>`
})
export class SlicePipeListComponent {
  collection: string[] = ['a', 'b', 'c', 'd'];
}

<li>b</li>
<li>c</li>

@Component({
  selector: 'slice-string-pipe',
  template: `<div>
    <p>{{str}}[0:4]: '{{str | slice:0:4}}' - output is expected to be 'abcd'</p>
    <p>{{str}}[4:0]: '{{str | slice:4:0}}' - output is expected to be ''</p>
    <p>{{str}}[-4]: '{{str | slice:-4}}' - output is expected to be 'ghij'</p>
    <p>{{str}}[-4:-2]: '{{str | slice:-4:-2}}' - output is expected to be 'gh'</p>
    <p>{{str}}[-100]: '{{str | slice:-100}}' - output is expected to be 'abcdefghij'</p>
    <p>{{str}}[100]: '{{str | slice:100}}' - output is expected to be ''</p>
  </div>`
})
export class SlicePipeStringComponent {
  str: string = 'abcdefghij';
}

number_expression | number[:digitInfo]

{minIntegerDigits}.{minFractionDigits}-{maxFractionDigits}

@Component({
  selector: 'number-pipe',
  template: `<div>
    <p>e (no formatting): {{e}}</p>
    <p>e (3.1-5): {{e | number:'3.1-5'}}</p>  //整数最小有3位。小数最小有一位，最多有5位 
    <p>pi (no formatting): {{pi}}</p>
    <p>pi (3.5-5): {{pi | number:'3.5-5'}}</p>   //整数最小3位，小数只能有5位
  </div>`
})
export class NumberPipeComponent {
  pi: number = 3.141592;
  e: number = 2.718281828459045;
}

<p>{{number | number:'1.2-2'}}</p>   

<p>{{number | percent:'1.2-2'}}</p> 

@Component({
  selector: 'lowerupper-pipe',
  template: `<div>
    <label>Name: </label><input #name (keyup)="change(name.value)" type="text">
    <p>In lowercase: <pre>'{{value | lowercase}}'</pre>　　　　　　　　//将value转换成小写
    <p>In uppercase: <pre>'{{value | uppercase}}'</pre>　　　　　　　　//将value转换成大写
  </div>`
})
export class LowerUpperPipeComponent {
  value: string;
  change(value: string) { this.value = value; }
}

{{ today | date[:format] }}

'medium'：等同于'yMMMdjms'（例如Sep 3, 2010, 12:05:08 PMfor en-US）
'short'：等同于'yMdjm'（例如9/3/2010, 12:05 PMfor en-US）
'fullDate'：等同于'yMMMMEEEEd'（例如Friday, September 3, 2010for en-US）
'longDate'：等同于'yMMMMd'（例如September 3, 2010for en-US）
'mediumDate'：等同于'yMMMd'（例如Sep 3, 2010for en-US）
'shortDate'：等同于'yMd'（例如9/3/2010for en-US）
'mediumTime'：等同于'jms'（例如12:05:08 PMfor en-US）
'shortTime'：等同于'jm'（例如12:05 PMfor en-US）

{{ today | date:"y-MM-dd"}}　　//2017-03-14

{{ today | date:"mmss"}}　　//11:35

{{ today | date:"y年MM月dd日HH时mm分ss秒"}}　　//2017年03月14日11时37分12秒

@Component({
  selector: 'date-pipe',
  template: `<div>
    <p>Today is {{today | date}}</p>
    <p>Or if you prefer, {{today | date:'fullDate'}}</p>
    <p>The time is {{today | date:'jmZ'}}</p>
  </div>`
})
export class DatePipeComponent {
  today: number = Date.now();
}

@Component({
  selector: 'json-pipe',
  template: `<div>
    <p>Without JSON pipe:</p>
    <pre>{{object}}</pre>
    <p>With JSON pipe:</p>
    <pre>{{object | json}}</pre>
  </div>`
})
export class JsonPipeComponent {
  object: Object = {foo: 'bar', baz: 'qux', nested: {xyz: 3, numbers: [1, 2, 3, 4, 5]}};
}

@Component({
  selector: 'currency-pipe',
  template: `<div>
    <p>A: {{a | currency:'USD':false}}</p>
    <p>B: {{b | currency:'USD':true:'4.2-2'}}</p>
  </div>`
})
export class CurrencyPipeComponent {
  a: number = 0.259;
  b: number = 1.3495;
}