functional-title-uppercase.js

const compose = (...fns) => data =>
  fns.reduceRight((value, fn) => fn(value), data)

const trim = str => str.trim()

const split = separator => str => str.split(separator)

const notEmpty = str => str.length > 0

const removeEmpty = parts => parts.filter(notEmpty)

const words = compose(removeEmpty, split(' '), trim)

const upperCapital = str => str.charAt(0).toUpperCase() + str.substr(1)
const capitalize = filtered => filtered.map(upperCapital)
const join = separator => arr => arr.join(separator)

const titleCase = compose(join(' '), capitalize, words)

titleCase('this is a test')