+++ /dev/null
-import { Operator } from '../Operator';
-import { Subscriber } from '../Subscriber';
-import { Subscription } from '../Subscription';
-import { async } from '../scheduler/async';
-import { Observable } from '../Observable';
-import { ThrottleConfig, defaultThrottleConfig } from './throttle';
-import { MonoTypeOperatorFunction, SchedulerLike, TeardownLogic } from '../types';
-
-/**
- * Emits a value from the source Observable, then ignores subsequent source
- * values for `duration` milliseconds, then repeats this process.
- *
- * <span class="informal">Lets a value pass, then ignores source values for the
- * next `duration` milliseconds.</span>
- *
- * 
- *
- * `throttleTime` emits the source Observable values on the output Observable
- * when its internal timer is disabled, and ignores source values when the timer
- * is enabled. Initially, the timer is disabled. As soon as the first source
- * value arrives, it is forwarded to the output Observable, and then the timer
- * is enabled. After `duration` milliseconds (or the time unit determined
- * internally by the optional `scheduler`) has passed, the timer is disabled,
- * and this process repeats for the next source value. Optionally takes a
- * {@link SchedulerLike} for managing timers.
- *
- * ## Examples
- *
- * #### Limit click rate
- *
- * Emit clicks at a rate of at most one click per second
- * ```ts
- * import { fromEvent } from 'rxjs';
- * import { throttleTime } from 'rxjs/operators';
- *
- * const clicks = fromEvent(document, 'click');
- * const result = clicks.pipe(throttleTime(1000));
- * result.subscribe(x => console.log(x));
- * ```
- *
- * #### Double Click
- *
- * The following example only emits clicks which happen within a subsequent
- * delay of 400ms of the previous click. This for example can emulate a double
- * click. It makes use of the `trailing` parameter of the throttle configuration.
- *
- * ```ts
- * import { fromEvent, asyncScheduler } from 'rxjs';
- * import { throttleTime, withLatestFrom } from 'rxjs/operators';
- *
- * // defaultThottleConfig = { leading: true, trailing: false }
- * const throttleConfig = {
- * leading: false,
- * trailing: true
- * }
- *
- * const click = fromEvent(document, 'click');
- * const doubleClick = click.pipe(
- * throttleTime(400, asyncScheduler, throttleConfig)
- * );
- *
- * doubleClick.subscribe((throttleValue: Event) => {
- * console.log(`Double-clicked! Timestamp: ${throttleValue.timeStamp}`);
- * });
- * ```
- *
- * If you enable the `leading` parameter in this example, the output would be the primary click and
- * the double click, but restricts additional clicks within 400ms.
- *
- * @see {@link auditTime}
- * @see {@link debounceTime}
- * @see {@link delay}
- * @see {@link sampleTime}
- * @see {@link throttle}
- *
- * @param {number} duration Time to wait before emitting another value after
- * emitting the last value, measured in milliseconds or the time unit determined
- * internally by the optional `scheduler`.
- * @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for
- * managing the timers that handle the throttling.
- * @param {Object} config a configuration object to define `leading` and
- * `trailing` behavior. Defaults to `{ leading: true, trailing: false }`.
- * @return {Observable<T>} An Observable that performs the throttle operation to
- * limit the rate of emissions from the source.
- * @method throttleTime
- * @owner Observable
- */
-export function throttleTime<T>(duration: number,
- scheduler: SchedulerLike = async,
- config: ThrottleConfig = defaultThrottleConfig): MonoTypeOperatorFunction<T> {
- return (source: Observable<T>) => source.lift(new ThrottleTimeOperator(duration, scheduler, config.leading, config.trailing));
-}
-
-class ThrottleTimeOperator<T> implements Operator<T, T> {
- constructor(private duration: number,
- private scheduler: SchedulerLike,
- private leading: boolean,
- private trailing: boolean) {
- }
-
- call(subscriber: Subscriber<T>, source: any): TeardownLogic {
- return source.subscribe(
- new ThrottleTimeSubscriber(subscriber, this.duration, this.scheduler, this.leading, this.trailing)
- );
- }
-}
-
-/**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
-class ThrottleTimeSubscriber<T> extends Subscriber<T> {
- private throttled: Subscription;
- private _hasTrailingValue: boolean = false;
- private _trailingValue: T = null;
-
- constructor(destination: Subscriber<T>,
- private duration: number,
- private scheduler: SchedulerLike,
- private leading: boolean,
- private trailing: boolean) {
- super(destination);
- }
-
- protected _next(value: T) {
- if (this.throttled) {
- if (this.trailing) {
- this._trailingValue = value;
- this._hasTrailingValue = true;
- }
- } else {
- this.add(this.throttled = this.scheduler.schedule<DispatchArg<T>>(dispatchNext, this.duration, { subscriber: this }));
- if (this.leading) {
- this.destination.next(value);
- } else if (this.trailing) {
- this._trailingValue = value;
- this._hasTrailingValue = true;
- }
- }
- }
-
- protected _complete() {
- if (this._hasTrailingValue) {
- this.destination.next(this._trailingValue);
- this.destination.complete();
- } else {
- this.destination.complete();
- }
- }
-
- clearThrottle() {
- const throttled = this.throttled;
- if (throttled) {
- if (this.trailing && this._hasTrailingValue) {
- this.destination.next(this._trailingValue);
- this._trailingValue = null;
- this._hasTrailingValue = false;
- }
- throttled.unsubscribe();
- this.remove(throttled);
- this.throttled = null;
- }
- }
-}
-
-interface DispatchArg<T> {
- subscriber: ThrottleTimeSubscriber<T>;
-}
-
-function dispatchNext<T>(arg: DispatchArg<T>) {
- const { subscriber } = arg;
- subscriber.clearThrottle();
-}
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