Welshman Docs / @welshman/lib / countBy

Function: countBy()

countBy<T, K>(f, xs): Map<K, number>

Defined in: packages/lib/src/Tools.ts:649

Counts array elements by key function

Type Parameters

T

T

K

K

Parameters

f

(x) => K

Function to generate group key

xs

T[]

Array to count entries

Returns

Map<K, number>

Map of counts