export function commonChars(a: string, b: string): number {
  const aArray = [...new Set(a.toLocaleLowerCase().split(''))]
  const bSet = new Set(b.toLocaleLowerCase())

  const total = aArray.reduce((total, letter) => {
    if (bSet.has(letter)) return total + 1
      else return total
  }, 0)

  return total;
}