RXJS:TypeError:this._subscribe 不是函数 [英] RXJS: TypeError: this._subscribe is not a function

问题描述

我正在将 ionic 3.8 应用程序迁移到 3.9.2.此迁移包括对 RXJS 5.5 的更新

I'm migrating an ionic 3.8 app to 3.9.2. This migration includes an update to RXJS 5.5

我现在遇到了这个错误:

I'm now experiencing this error:

TypeError: this._subscribe 不是一个函数.(在'this._subscribe(sink)'中，'this._subscribe'是t的一个实例)

经过几个小时的调试，我发现这部分代码与错误有关:

After hours of debugging, I found out that this code portion is related to the error:

protected observeConnectionState() {

    // rxjs/observable/of
    of(new Event('disconnect'))
        .pipe(
            // rxjs/operators/merge
            merge(connect$),
            merge(disconnect$),

            // Map eventname to string (rxjs/operators/map)
            map((e: IEvent) => {
                return e.eventName == 'connect' ? 'connected' : 'disconnected';
            })
        )
        // Apply to class context
        .subscribe((newConnectionState) => {
            // this.connectionState$ is a BehaviorSubject
            this.connectionState$.next(newConnectionState);
        });
}

附加信息

• RXJS 代码中有两个地方，我是否能够找到 this._subscribe:Observable.ts 第 203 行 和 Observable.ts 第 208 行.

推荐答案

嗯，我找到了问题所在.而且它与 Cordova 无关.

Well, I found the problem. And it's not related to Cordova.

对于遇到此问题的其他人:忘记堆栈跟踪 - 它没用.在我的 this.connectionState$ 订阅者的情况下，我试图从一个承诺创建一个 Observable.但我做错了.

For other people encountering this problem: Forget the stack trace - it's useless. In my case in a subscriber of this.connectionState$ I tried to create an Observable from a promise. But I did it wrong.

这是错的:

import { Observable } from 'rxjs/Observable';
//...
const myObservable$ = Observable.create(myPromise);

应该是这样的:

import { fromPromise } from 'rxjs/observable/fromPromise';
// ...
const myObservable$ = fromPromise(myPromise);

这篇关于RXJS:TypeError:this._subscribe 不是函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！