Additional JS String Case

jsCase.js

export const capitalCase = (str) =>
  str && 
  str.toString().charAt(0).toUpperCase() 
    + str.toString().slice(1).toLowerCase();

export const properCase = (str) =>
  str &&
  str
    .toString()
    .split(' ')
    .map((word) => capitalCase(word))
    .join(' ');