angular-cn/public/docs/_examples/pipes/ts/app/fetch-json.pipe.ts

29 lines
640 B
TypeScript

// #docregion
import {Pipe, PipeTransform} from 'angular2/core';
import {Http} from 'angular2/http';
// #docregion pipe-metadata
@Pipe({
name: 'fetch',
pure: false
})
// #enddocregion pipe-metadata
export class FetchJsonPipe implements PipeTransform{
private fetched:any = null;
private prevUrl = '';
constructor(private _http: Http) { }
transform(url:string):any {
if (url !== this.prevUrl) {
this.prevUrl = url;
this.fetched = null;
this._http.get(url)
.map( result => result.json() )
.subscribe( result => this.fetched = result )
}
return this.fetched;
}
}