skipWhile

Skips values from the source observable while the predicate returns true. Once the predicate returns false, all subsequent values pass through.

Marble Diagram

skipWhile(x => x < 5)

Example

//  Timeline:
//
//  num$        1     2     3     4     5     6     7     1     2
//  skipped$                            5     6     7     1     2
//              |-------- skip --------|
//
//  Explanation:
//  - skipWhile skips values while the predicate returns true
//  - Once the predicate returns false, all subsequent values pass through
//  - Unlike filter, the predicate is never checked again after the first false

const num$ = source<number>();

const skipped$ = num$.pipe(skipWhile((x) => x < 5));

const valueHistory: number[] = [];

skipped$.subscribe((x) => {
    valueHistory.push(x);
});

num$.next(1); // nothing logged

num$.next(2); // nothing logged

num$.next(3); // nothing logged

num$.next(4); // nothing logged

num$.next(5); // logs: 5

assert.deepStrictEqual(valueHistory, [5]);

num$.next(6); // logs: 6

assert.deepStrictEqual(valueHistory, [5, 6]);

num$.next(7); // logs: 7

assert.deepStrictEqual(valueHistory, [5, 6, 7]);

num$.next(1); // logs: 1

num$.next(2); // logs: 2

assert.deepStrictEqual(valueHistory, [5, 6, 7, 1, 2]);

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