在 http 请求结束时执行额外的 observable/promise

Question

我有一个拦截器，当请求从服务器返回时我需要chain/execute一个promise/observable。我如何在 rxjs 6 中执行此操作？

intercept(): Observable<HttpEvent<any>> {
    return next.handle(request)[DO-SOMETHING]
}

Answer 1

如需修改http事件：

return next.handle(request).pipe(
    mergeMap(request => yourPromiseOrObservable));

mergeMap 是做什么的？

Projects each source value to an Observable which is merged in the output Observable.

如果不需要修改http事件：

return next.handle(request).pipe(
    tap(request => yourPromise.then(_ => ;)));

tap 是做什么的？

Perform a side effect for every emission on the source Observable, but return an Observable that is identical to the source.

或者，如果您需要等待承诺但不修改请求：

return next.handle(request).pipe(
    delayWhen(request => from(yourPromise)));

delayWhen 是做什么的？

Delays the emission of items from the source Observable by a given time span determined by the emissions of another Observable.

execute extra observable/promise at the end of the http request