如何清理/清除 rxjs 中 SubjectReplay 实例的缓存? [英] How to clean/clear cache of a SubjectReplay instance in rxjs?

问题描述

我有一个 SubjectReplay，我想将它重置为没有缓存值，所以在重置后下一个订阅者不会获得历史记录?

I have a SubjectReplay and I would like to reset it to no cache values so after this reset the next subscriber doesn't get the history?

示例

• 新主题重播
• subject.next(1)
• 重置主题 <- 这个问题
• subject.subscribe()//不应该收到 1

我该怎么做?我需要主题是同一个实例.

how can I do this? I need the subject to be the same instance.

推荐答案

对于您的要求，我想到的最佳方式

The best way that comes to my mind with your requirement

我需要主题是同一个实例

I need the subject to be the same instance

应该有以下可观察的:

// This is your input
const source$: Observable<T>;

const proxy$ = new ReplaySubject<T>(n);
const reset$ = new BehaviorSubject<number>(0);

现在重要的是，我们在 source$ 上发出之前连接以下内容:

Now it's important that we hook up the following before you emit on source$:

source$.pipe(timestamp()).subscribe(proxy$);

最后，您可以像这样公开您的数据:

Then, finally, you can expose your data like this:

const data$ = proxy$.pipe(
  withLatestFrom(reset$),
  filter(([timedItem, resetTimestamp]) => timedItem.timestamp > resetTimestamp),
  map(([timedItem]) => timedItem.value),
);

您现在可以使用 reset$.next(+new Date()) 来触发重置.

You can now use reset$.next(+new Date()) to trigger the reset.

如果您可以确保为 source$ 提供带时间戳的值，则可以跳过 proxy$.

If you can make sure to provide timestamped values to source$, you can skip the proxy$.

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