timestamp
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 asyncScheduler
which simply returns Date.now()
(milliseconds since 1970/01/01
00:00:00:000) and therefore is of type number
.
Example
In this example there is a timestamp attached to the document's click events
import { fromEvent, timestamp } from 'rxjs';
const clickWithTimestamp = fromEvent(document, 'click').pipe(
timestamp()
);
// Emits data of type { value: PointerEvent, timestamp: number }
clickWithTimestamp.subscribe(data => {
console.log(data);
});
§Parameters
An object with a now()
method used to get the current timestamp.
§Return Type
A function that returns an Observable that attaches a timestamp to each item emitted by the source Observable indicating when it was emitted.