xdash API Reference / groupBy
Function: groupBy()
groupBy<
T,K>(arr,key):Record<K,T[]>
Defined in: src/array.ts:218
Groups an array of values by a key.
Type Parameters
T
T
K
K extends string | number | symbol
Parameters
arr
T[]
array to group
key
(x) => K
key to group by
Returns
Record<K, T[]>
the grouped array
Example
ts
groupBy([{ a: 1 }, { a: 2 }, { a: 1 }], x => x.a) // returns { 1: [{ a: 1 }, { a: 1 }], 2: [{ a: 2 }] }
groupBy(['foo', 'bar', 'hello', 'world'], x => x.length) // returns { 3: ['foo', 'bar'], 5: ['hello', 'world'] }