// #docregion // #docregion pure import { Pipe, PipeTransform } from '@angular/core'; import { Flyer } from './heroes'; @Pipe({ name: 'flyingHeroes' }) export class FlyingHeroesPipe implements PipeTransform { transform(allHeroes:Flyer[]) { // #docregion filter return allHeroes.filter(hero => hero.canFly); // #enddocregion filter } } // #enddocregion pure /////// Identical except for the pure flag // #docregion impure // #docregion pipe-decorator @Pipe({ name: 'flyingHeroes', pure: false }) // #enddocregion pipe-decorator export class FlyingHeroesImpurePipe extends FlyingHeroesPipe {} // #enddocregion impure