reduce

import { reduce } from "https://raw.githubusercontent.com/surma/observables-with-streams/28c55be6d855780c677fd1f4ba975f4d3144891d/src/index.ts";

Accumulates value, starting with v0 and applying f to each emitted item. If no items are emitted the promise is rejected.

async function reduce<U, T>(

f: ScanFunc<U, T>,

v0: U,

): Promise<U>;

reduce<U, T>(o: Observable<T>, f: ScanFunc<U, T>, v0: U): Promise<U>

Observable to reduce.

f: ScanFunc<U, T>

Reduce function called with the accumulated value so far and the current item. Should return a new accumulated value.

v0: U

Initial accumulator value.

Promise<U>

Promise that resolves with the accumulated value.