import { OperatorFunction, SchedulerLike, Timestamp as TimestampInterface } from '../types'; /** * Attaches a timestamp to each item emitted by an observable indicating when it was emitted * * The `timestamp` operator maps the *source* observable stream to an object of type * `{value: T, timestamp: R}`. The properties are generically typed. The `value` property contains the value * and type of the *source* observable. The `timestamp` is generated by the schedulers `now` function. By * default it uses the *async* scheduler which simply returns `Date.now()` (milliseconds since 1970/01/01 * 00:00:00:000) and therefore is of type `number`. * * ![](timestamp.png) * * ## Example * * In this example there is a timestamp attached to the documents click event. * * ```ts * import { fromEvent } from 'rxjs'; * import { timestamp } from 'rxjs/operators'; * * const clickWithTimestamp = fromEvent(document, 'click').pipe( * timestamp() * ); * * // Emits data of type {value: MouseEvent, timestamp: number} * clickWithTimestamp.subscribe(data => { * console.log(data); * }); * ``` * * @param scheduler * @return {Observable<Timestamp<any>>|WebSocketSubject<T>|Observable<T>} * @method timestamp * @owner Observable */ export declare function timestamp<T>(scheduler?: SchedulerLike): OperatorFunction<T, Timestamp<T>>; export declare class Timestamp<T> implements TimestampInterface<T> { value: T; timestamp: number; constructor(value: T, timestamp: number); }