skipLast

Skip a specified number of values before the completion of an observable.

skipLast<T>(skipCount: number): MonoTypeOperatorFunction<T>

Parameters

skipCount

Number of elements to skip from the end of the source Observable.

Returns

MonoTypeOperatorFunction<T>: A function that returns an Observable that skips the last count values emitted by the source Observable.

Description

Returns an observable that will emit values as soon as it can, given a number of skipped values. For example, if you skipLast(3) on a source, when the source emits its fourth value, the first value the source emitted will finally be emitted from the returned observable, as it is no longer part of what needs to be skipped.

All values emitted by the result of skipLast(N) will be delayed by N emissions, as each value is held in a buffer until enough values have been emitted that that the buffered value may finally be sent to the consumer.

After subscribing, unsubscribing will not result in the emission of the buffered skipped values.

Example

Skip the last 2 values of an observable with many values

import { of } from 'rxjs';
import { skipLast } from 'rxjs/operators';

const numbers = of(1, 2, 3, 4, 5);
const skipLastTwo = numbers.pipe(skipLast(2));
skipLastTwo.subscribe(x => console.log(x));

// Results in:
// 1 2 3
// (4 and 5 are skipped)

See Also

• skip
• skipUntil
• skipWhile
• take