83 lines
3.2 KiB
TypeScript
83 lines
3.2 KiB
TypeScript
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import { ThrottleConfig } from './throttle';
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import { MonoTypeOperatorFunction, SchedulerLike } from '../types';
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/**
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* Emits a value from the source Observable, then ignores subsequent source
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* values for `duration` milliseconds, then repeats this process.
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*
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* <span class="informal">Lets a value pass, then ignores source values for the
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* next `duration` milliseconds.</span>
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*
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* 
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*
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* `throttleTime` emits the source Observable values on the output Observable
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* when its internal timer is disabled, and ignores source values when the timer
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* is enabled. Initially, the timer is disabled. As soon as the first source
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* value arrives, it is forwarded to the output Observable, and then the timer
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* is enabled. After `duration` milliseconds (or the time unit determined
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* internally by the optional `scheduler`) has passed, the timer is disabled,
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* and this process repeats for the next source value. Optionally takes a
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* {@link SchedulerLike} for managing timers.
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*
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* ## Examples
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*
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* #### Limit click rate
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*
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* Emit clicks at a rate of at most one click per second
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* ```ts
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* import { fromEvent } from 'rxjs';
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* import { throttleTime } from 'rxjs/operators';
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*
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* const clicks = fromEvent(document, 'click');
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* const result = clicks.pipe(throttleTime(1000));
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* result.subscribe(x => console.log(x));
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* ```
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*
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* #### Double Click
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*
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* The following example only emits clicks which happen within a subsequent
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* delay of 400ms of the previous click. This for example can emulate a double
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* click. It makes use of the `trailing` parameter of the throttle configuration.
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*
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* ```ts
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* import { fromEvent, asyncScheduler } from 'rxjs';
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* import { throttleTime, withLatestFrom } from 'rxjs/operators';
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*
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* // defaultThottleConfig = { leading: true, trailing: false }
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* const throttleConfig = {
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* leading: false,
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* trailing: true
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* }
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*
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* const click = fromEvent(document, 'click');
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* const doubleClick = click.pipe(
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* throttleTime(400, asyncScheduler, throttleConfig)
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* );
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*
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* doubleClick.subscribe((throttleValue: Event) => {
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* console.log(`Double-clicked! Timestamp: ${throttleValue.timeStamp}`);
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* });
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* ```
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*
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* If you enable the `leading` parameter in this example, the output would be the primary click and
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* the double click, but restricts additional clicks within 400ms.
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*
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* @see {@link auditTime}
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* @see {@link debounceTime}
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* @see {@link delay}
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* @see {@link sampleTime}
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* @see {@link throttle}
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*
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* @param {number} duration Time to wait before emitting another value after
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* emitting the last value, measured in milliseconds or the time unit determined
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* internally by the optional `scheduler`.
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* @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for
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* managing the timers that handle the throttling.
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* @param {Object} config a configuration object to define `leading` and
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* `trailing` behavior. Defaults to `{ leading: true, trailing: false }`.
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* @return {Observable<T>} An Observable that performs the throttle operation to
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* limit the rate of emissions from the source.
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* @method throttleTime
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* @owner Observable
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*/
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export declare function throttleTime<T>(duration: number, scheduler?: SchedulerLike, config?: ThrottleConfig): MonoTypeOperatorFunction<T>;
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