RXJS可观察的枚举类型，类型为“可观察” <Type> &#39;不可分配给&#39;Type&#39;类型

Question

I am trying to observe the latest event that happens in a stream. Each event can be one of two types, represented by an enum. However I am getting a compilation error in the following example:

import { BehaviorSubject } from 'rxjs/Rx';


export enum FilterAction {
  RESET, UPDATE
}

export class FilterSomething {

  private _filterEvent: BehaviorSubject<FilterAction> = new BehaviorSubject(FilterAction.RESET);

  get filterEvent() {
    return this._filterEvent.asObservable(); // <-- behave.ts(14,12): error TS2322: Type 'Observable<FilterAction>' is not assignable to type 'FilterAction'
  }


  set filterEvent(action: FilterAction){
    this._filterEvent.next(action);
  }
}

Compilation error: behave.ts(14,12): error TS2322: Type 'Observable<FilterAction>' is not assignable to type 'FilterAction'

However when I use the generic any it compiles (and works).

set filterEvent(filterAction: any) {
   this._filterEvent.next(filterAction);
}

I suspect it's something to do with the enum values, as opposed to instances of FilterAction .

Answer 1

The problem is return type of your getter . Getter s and Setter s should take and return same type of parameter, which is FilterAction in your case. But your getter returns Observable<FilterAction> . Just do not use getter , change the name of the function. Then language service stop showing error. In language specification:

If both accessors include type annotations, the specified types must be identical.

You can check this out.