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RxJS:Share()可观察并向每个新订阅者发出最后一个值

angular2-services observable rxjs angular

aleixsuau · 技术社区 · 8 年前

我使用.share()在服务的所有订阅者之间共享一个可观察的:

@Injectable()
export class ChannelsService {
    private store: IChannel[] = [];
    private _own: BehaviorSubject<IChannel[]> = new BehaviorSubject([]);
    readonly own: Observable<IChannel[]> = this._own.asObservable().share();
    ...(the rest of the service basically makes CRUD http request and then calls this._own.next(result) to emit the result to all subscribers)
}

问题:

谢谢

3 回复 | 直到 8 年前

Graham francescalus 8 年前

你可能想要 shareReplay() (自RxJS 5.4.0起)或 publishReplay().refCount()

例如:

this._own.asObservable()
  .publishReplay(1)
  .refCount()
  .take(1);

Jota.Toledo 8 年前

一些小的改进:

@Injectable()
export class ChannelsService {
    private store: IChannel[] = [];
    private _own: BehaviorSubject<IChannel[]> = new BehaviorSubject([]);
    get own(){
      this._own.asObservable();
    }
}

现在,您可以在组件中执行以下操作:

channels$: Observable<IChannel[]> = this.service.own;

别忘了

Jorge Rodríguez Galán 8 年前

您的结果是使用不带初始化值的共享时的预期结果。 Explanation

const subject = new Rx.Subject();

const behaviorWithoutShortcut = subject
  .multicast(new Rx.BehaviorSubject(null))
  .refCount()
  .filter(function (x) { return x !== null; });

const behaviorWithShortcut = subject
  .publishBehavior(null)
  .refCount()
  .filter(function (x) { return x !== null; });

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