Discussion on: #4.Basic algorithms problems for frontend developers.

const findMostUsedLetter = (str) => {
  const filteredStrToArr = str
    .replace(/[^a-zA-Z]/g, '')
    .split('')
    .sort()

  return filteredStrToArr.reduce((a, b, index, arr) => (
    arr.filter((v) => v === a).length >= arr.filter((v) => v === b).length
      ? a
      : b
  ), null)
}

console.log(findMostUsedLetter('hey there my friend'))