RxJS油门行为;立即获得第一个价值 [英] RxJS throttle behavior; get first value immediately

问题描述

示例Plunkr： https://plnkr.co/edit/NZwb3ol8CbZFtSc6Q9zm?p=preview

我知道rxjs有这3种限制方法（5.0 beta.4）：

I am aware that there are these 3 throttle methods for rxjs (5.0 beta.4):

auditTime（）， throttleTime（）和 debounceTime（）

我正在寻找的行为是lodash默认在油门上执行的行为：

The behavior I am looking for is the one lodash does by default on throttle:

• 1）立即给我第一个值！


• 2）连续值，保持给定延迟的值，然后发出最后一个值


• 3）当油门延迟到期时，返回状态（1）

理论上这应该是这样的：

In theory this should look like:

inputObservable
  .do(() => cancelPreviousRequest())
  .throttleTime(500)
  .subscribe((value) => doNextRequest(value))

但是

• throttleTime 永远不会给我最后一个值，如果在油门超时中发出


• debounceTime 不会立即触发


• auditTime 不会立即触发

• throttleTime never gives me the last value, if emitted in the throttle timeout
• debounceTime doesn't trigger immediately
• auditTime doesn't trigger immediately

我可以组合任何rxjs方法来实现所描述的行为吗？

Could I combine any of the rxjs methods to achieve the described behavior?

推荐答案

我拿了auditTime运算符并更改了2行实现理想的行为。

I took the auditTime operator and changed 2 lines to achieve the desired behavior.

新的plunker： https://plnkr.co/edit/4NkXsOeJOSrLUP9WEtp0?p=preview

New plunker: https://plnkr.co/edit/4NkXsOeJOSrLUP9WEtp0?p=preview

原文：

• https://github.com /ReactiveX/rxjs/blob/master/src/operator/auditTime.ts

• https://github.com/ReactiveX/rxjs/blob/master/src/operator/auditTime.ts

更改：

：

protected _next(value: T): void {
  this.value = value;
  this.hasValue = true;
  if (!this.throttled) {
    this.add(this.throttled = this.scheduler.schedule(dispatchNext, this.duration, this));
  }
}

clearThrottle(): void {
  const { value, hasValue, throttled } = this;
  if (throttled) {
    this.remove(throttled);
    this.throttled = null;
    throttled.unsubscribe();
  }
  if (hasValue) {
    this.value = null;
    this.hasValue = false;
    this.destination.next(value);
  }
}

到（auditTimeImmediate）：

to (auditTimeImmediate):

protected _next(value: T): void {
    this.value = value;
    this.hasValue = true;
    if (!this.throttled) {
        // change 1:
        this.clearThrottle();
    }
}

clearThrottle(): void {
    const { value, hasValue, throttled } = this;
    if (throttled) {
        this.remove(throttled);
        this.throttled = null;
        throttled.unsubscribe();
    }
    if (hasValue) {
        this.value = null;
        this.hasValue = false;
        this.destination.next(value);
        // change 2:
        this.add(this.throttled = this.scheduler.schedule(dispatchNext, this.duration, this));
    }
}

所以我在价值<$后开始超时c $ c> next ed。

用法：

inputObservable
  .do(() => cancelPreviousRequest())
  .auditTimeImmediate(500)
  .subscribe((value) => doNextRequest(value))

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