Getting Name Capitals in JavaScript

name-capitals.js

const splitWords = phrase => phrase.split(' ')
const firstLetter = word => word.charAt(0)
const lastLetter = word => word.charAt(word.length - 1)

const initialLetter = words => words
  .map(word => word.charAt(0))
  .join('')

const firstAndLastLetter = word => [
  firstLetter(word),
  lastLetter(word)
].join('')

const getNameCapitals = name => firstAndLastLetter(
  initialLetter(
    splitWords(name)
  )
)

getNameCapitals('Isac Fadoni Leite') // IL