foreword/test/array/countBy.js

A JavaScript library for functional data transformation

const test = require('tape')
const { countBy } = require('../../array')

test('array countBy', t => {
  const result1 = countBy(Math.floor)([4.2, 6.1, 6.4])
  const result2 = countBy(x => x.length)(['one', 'two', 'three'])

  t.same(result1, { 4: 1, 6: 2 })
  t.same(result2, { 3: 2, 5: 1 })

  t.end()
})