主题是可观察的一种特殊类型，它允许将值多播到许多观察者。主题就像 EventEmitters。

class Subject<T> extends Observable implements SubscriptionLike {
  static create: Function
  constructor()
  observers: Observer<T>[]
  closed: false
  isStopped: false
  hasError: false
  thrownError: any
  lift<R>(operator: Operator<T, R>): Observable<R>
  next(value?: T)
  error(err: any)
  complete()
  unsubscribe()
  _trySubscribe(subscriber: Subscriber<T>): TeardownLogic
  _subscribe(subscriber: Subscriber<T>): Subscription
  asObservable(): Observable<T>

 
  // inherited from index/Observable
  static create: Function
  static if: typeof iif
  static throw: typeof throwError
  constructor(subscribe?: (this: Observable<T>, subscriber: Subscriber<T>) => TeardownLogic)
  _isScalar: boolean
  source: Observable<any>
  operator: Operator<any, T>
  lift<R>(operator: Operator<T, R>): Observable<R>
  subscribe(observerOrNext?: NextObserver<T> | ErrorObserver<T> | CompletionObserver<T> | ((value: T) => void), error?: (error: any) => void, complete?: () => void): Subscription
  _trySubscribe(sink: Subscriber<T>): TeardownLogic
  forEach(next: (value: T) => void, promiseCtor?: PromiseConstructorLike): Promise<void>
  pipe(...operations: OperatorFunction<any, any>[]): Observable<any>
  toPromise(promiseCtor?: PromiseConstructorLike): Promise<T>
}

子类

• BehaviorSubject
• ReplaySubject
• AsyncSubject

描述

每个主题都是一个可观察者和一个观察者。您可以订阅主题，也可以在提要值以及错误和完成旁边调用。

静态特性

建设者

constructor()参量没有参数。

物产

方法

电梯（） lift<R>(operator: Operator<T, R>): Observable<R>

returnsObservable<R>

_trySubscribe（）
_trySubscribe(subscriber: Subscriber<T>): TeardownLogic

returnsTeardownLogic