import { AsyncReducer } from "https://deno.land/x/rimbu@1.2.1/mod.ts";
const { groupBy } = AsyncReducer;
Returns an AsyncReducer that uses the valueToKey function to calculate a key for each value, and feeds the tuple of the key and the value to the
collector reducer. Finally, it returns the output of the collector. If no collector is given, the default collector will return a JS multimap
of the type Map<K, V[]>.
type
{ <T, K, R, T2 extends readonly [K, T] = [K, T]>(valueToKey: (value: T, index: number) => MaybePromise<K>, options: { collector: AsyncReducer.Accept<[K, T] | T2, R>; }): AsyncReducer<T, R>; <T, K>(valueToKey: (value: T, index: number) => MaybePromise<K>, options?: { collector?: undefined; }): AsyncReducer<T, Map<K, T[]>>; }
type
{ <T, K, R, T2 extends readonly [K, T] = [K, T]>(valueToKey: (value: T, index: number) => MaybePromise<K>, options: { collector: AsyncReducer.Accept<[K, T] | T2, R>; }): AsyncReducer<T, R>; <T, K>(valueToKey: (value: T, index: number) => MaybePromise<K>, options?: { collector?: undefined; }): AsyncReducer<T, Map<K, T[]>>; }