Lazy | /mod.ts | better_iterators@v1.2.1

method Lazy.prototype.groupBy

import { Lazy } from "https://deno.land/x/better_iterators@v1.2.1/mod.ts";

groupBy<Key>(keyFn: Transform<T, Key>): Map<Key, T[]>

Given keyFn, use it to extract a key from each item, and create a Map grouping items by that key.

groupBy<Key, Value>(keyFn: Transform<T, Key>, valueFn: Transform<T, Value>): Map<Key, Value[]>

Adds a valueFn to extract that value (instead of T) into a group.

Given keyFn, use it to extract a key from each item, and create a Map grouping items by that key.

Type Parameters

Key

Map<Key, T[]>

Adds a valueFn to extract that value (instead of T) into a group.

Key

Value

Map<Key, Value[]>