scanObservablePipe

Alternative: scan$$$

Inlined: scanObservable, scan$$

Types

function scanObservablePipe<GIn, GOut>(
  scanFunction: IScanFunction<GIn, GOut>,
  initialValue: GOut,
): IObservablePipe<GIn, GOut>

Definition

Applies an accumulator (or "reducer function") to each value from the source Observable from an initial value (second argument). This accumulated value is then emitted.

Diagram

Algorithm

Example

Example

Compute the sum of incoming values

const subscribe = pipe$$(of(0, 1, 2, 3), [
  scan$$$((sum: number, value: number): number => {
    return sum + value;
  }, 0),
]);

subscribe((value) => {
  console.log(value);
});

Output:

0
1
3
6