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