skip
signature: skip(the: Number): Observable
skip(the: Number): Observable
Skip the provided number of emitted values.
Why use skip
?
skip
?Skip allows you to ignore the first x emissions from the source. Generally skip
is used when you have an observable that always emits certain values on subscription that you wish to ignore. Perhaps those first few aren't needed or you are subscribing to a Replay
or BehaviorSubject
and do not need to act on the initial values. Reach for skip
if you are only concerned about later emissions.
You could mimic skip
by using filter
with indexes. Ex. .filter((val, index) => index > 1)
Examples
Example 1: Skipping values before emission
( StackBlitz | jsBin | jsFiddle )
// RxJS v6+
import { interval } from 'rxjs';
import { skip } from 'rxjs/operators';
//emit every 1s
const source = interval(1000);
//skip the first 5 emitted values
const example = source.pipe(skip(5));
//output: 5...6...7...8........
const subscribe = example.subscribe(val => console.log(val));
Example 2: Short hand for a specific filter use case
( StackBlitz | jsBin | jsFiddle )
// RxJS v6+
import { from } from 'rxjs';
import { skip, filter } from 'rxjs/operators';
const numArrayObs = from([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
// 3,4,5...
const skipObs = numArrayObs.pipe(skip(2)).subscribe(console.log);
// 3,4,5...
const filterObs = numArrayObs
.pipe(filter((val, index) => index > 1))
.subscribe(console.log);
//Same output!
Additional Resources
skip ๐ฐ - Official docs
Filtering operator: take, first, skip ๐ฅ ๐ต - Andrรฉ Staltz
๐ Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/skip.ts
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