client/src/app/videos/recommendations/recommended-videos.store.ts

   1 import { Observable, ReplaySubject } from 'rxjs'
   2 import { map, shareReplay, switchMap, take } from 'rxjs/operators'
   3 import { Inject, Injectable } from '@angular/core'
   4 import { Video } from '@app/shared/shared-main'
   5 import { RecentVideosRecommendationService } from './recent-videos-recommendation.service'
   6 import { RecommendationInfo } from './recommendation-info.model'
   7 import { RecommendationService } from './recommendations.service'
   8
   9 /**
  10  * This store is intended to provide data for the RecommendedVideosComponent.
  11  */
  12 @Injectable()
  13 export class RecommendedVideosStore {
  14   public readonly recommendations$: Observable<Video[]>
  15   public readonly hasRecommendations$: Observable<boolean>
  16   private readonly requestsForLoad$$ = new ReplaySubject<RecommendationInfo>(1)
  17
  18   constructor (
  19     @Inject(RecentVideosRecommendationService) private recommendations: RecommendationService
  20   ) {
  21     this.recommendations$ = this.requestsForLoad$$.pipe(
  22       switchMap(requestedRecommendation => {
  23         return this.recommendations.getRecommendations(requestedRecommendation)
  24                               .pipe(take(1))
  25       }),
  26       shareReplay()
  27     )
  28
  29     this.hasRecommendations$ = this.recommendations$.pipe(
  30       map(otherVideos => otherVideos.length > 0)
  31     )
  32   }
  33
  34   requestNewRecommendations (recommend: RecommendationInfo) {
  35     this.requestsForLoad$$.next(recommend)
  36   }
  37 }