blob: ce684a3fe471e4ffda6fac10c51ff15431743964 [file] [log] [blame]
import { Observable } from '../Observable';
import { SchedulerLike } from '../types';
/**
* Creates an Observable that starts emitting after an `dueTime` and
* emits ever increasing numbers after each `period` of time thereafter.
*
* <span class="informal">Its like {@link index/interval}, but you can specify when
* should the emissions start.</span>
*
* ![](timer.png)
*
* `timer` returns an Observable that emits an infinite sequence of ascending
* integers, with a constant interval of time, `period` of your choosing
* between those emissions. The first emission happens after the specified
* `dueTime`. The initial delay may be a `Date`. By default, this
* operator uses the {@link asyncScheduler} {@link SchedulerLike} to provide a notion of time, but you
* may pass any {@link SchedulerLike} to it. If `period` is not specified, the output
* Observable emits only one value, `0`. Otherwise, it emits an infinite
* sequence.
*
* ## Examples
* ### Emits ascending numbers, one every second (1000ms), starting after 3 seconds
* ```ts
* import { timer } from 'rxjs';
*
* const numbers = timer(3000, 1000);
* numbers.subscribe(x => console.log(x));
* ```
*
* ### Emits one number after five seconds
* ```ts
* import { timer } from 'rxjs';
*
* const numbers = timer(5000);
* numbers.subscribe(x => console.log(x));
* ```
* @see {@link index/interval}
* @see {@link delay}
*
* @param {number|Date} [dueTime] The initial delay time specified as a Date object or as an integer denoting
* milliseconds to wait before emitting the first value of 0`.
* @param {number|SchedulerLike} [periodOrScheduler] The period of time between emissions of the
* subsequent numbers.
* @param {SchedulerLike} [scheduler=async] The {@link SchedulerLike} to use for scheduling
* the emission of values, and providing a notion of "time".
* @return {Observable} An Observable that emits a `0` after the
* `dueTime` and ever increasing numbers after each `period` of time
* thereafter.
* @static true
* @name timer
* @owner Observable
*/
export declare function timer(dueTime?: number | Date, periodOrScheduler?: number | SchedulerLike, scheduler?: SchedulerLike): Observable<number>;