combineLatest 与 BehaviourSubject.asObservable 导致流是预期错误答案

【问题标题】：combineLatest with BehaviourSubject.asObservable causing stream was expected errorcombineLatest 与 BehaviourSubject.asObservable 导致流是预期错误
【发布时间】：2021-03-05 11:44:45
【问题描述】：

我正在尝试将 combineLatest 与 BehaviourSubject.asObservable 一起使用，但出现此错误：

TypeError: You provided 'function () {
        return this.ctaButtonSpinnerTriggered.asObservable();
    }' where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.

private ctaButtonSpinnerTriggered: BehaviorSubject<
    boolean
> = new BehaviorSubject(false);

public isCtaButtonSpinnerTriggered(): Observable<boolean> {
    return this.ctaButtonSpinnerTriggered.asObservable();
}

public setCtaButtonSpinnerTriggered(isDisabled: boolean): void {
    this.ctaButtonSpinnerTriggered.next(isDisabled);
}

public get showCtaSpinner(): Observable<boolean> {
    return combineLatest([
        this.ctaDisabled,
        this.isCtaButtonSpinnerTriggered,
    ]).pipe(
        map(
            ([ctaDisabled, isCtaButtonSpinnerTriggered]: [
                boolean,
                boolean
            ]) => {
                console.log(
                    !ctaDisabled,
                    isCtaButtonSpinnerTriggered,
                    'ctaDisabled + isCtaButtonSpinnerTriggered'
                );
                return !ctaDisabled && isCtaButtonSpinnerTriggered;
            }
        )
    );
}

有什么想法可以正确实现 combineLatest 和 BehaviourSubject 吗？

【问题讨论】：

标签： angular rxjs behaviorsubject rxjs-observables

【解决方案1】：

改变

return combineLatest([
        this.ctaDisabled,
        this.isCtaButtonSpinnerTriggered,
    ])

到

return combineLatest([
        this.ctaDisabled,
        this.isCtaButtonSpinnerTriggered(), // note the parentheses here
    ])

因为它不是一个 getter 函数。

要将您的属性设置为 getter/setter，请将其更改为：

private ctaButtonSpinnerTriggered: BehaviorSubject<
    boolean
> = new BehaviorSubject(false);

public get isCtaButtonSpinnerTriggered(): Observable<boolean> {
    return this.ctaButtonSpinnerTriggered.asObservable();
}

public set isCtaButtonSpinnerTriggered(isDisabled: boolean): void {
    this.ctaButtonSpinnerTriggered.next(isDisabled);
}

并将其用作

return combineLatest([
        this.ctaDisabled,
        this.isCtaButtonSpinnerTriggered,
    ])

【讨论】：