countBy

Creates an object composed of keys generated from the results of running each element of collection through iteratee. The corresponding value of each key is the number of times the key was returned by iteratee.

Signature

countBy<T>(collection: T[], iteratee: ((value: T) => PropertyKey) | keyof T): Record<PropertyKey, number>

Parameters

Returns

Record<PropertyKey, number> - Returns the composed aggregate object

Examples

import { countBy } from 'dashlite'

const result = countBy([6.1, 4.2, 6.3], Math.floor)
console.log(result)

import { countBy } from 'dashlite'

const users = [
  { role: 'admin' },
  { role: 'user' },
  { role: 'admin' }
]
const result = countBy(users, 'role')
console.log(result)