exercise to move capital letter to the front of a string

uppercase-to-front.js

/**
 * Create a function that moves all capital letters to the front of
 * a string/word. Keep the original relative
 * order of all letters the same.
 *
 * Example:
 *
 * "hApPy" ➞ "APhpy"
 */

 function inRange(number, starts, end) {
  return ( (number - starts) * (number - end) <= 0 )
 }

 function sortStr(str) {
   // solution 1
   // return str.split('').sort((a,b) => a > b ? 1 : a === b ? 0 : - 1).join('')

   // sollution 2 (with regexp)
  // const lowerCaseRegexp = /[a-z]/
  // return [...str].sort((a,b) => lowerCaseRegexp.test(a) ? 1 : lowerCaseRegexp.test(b) ? -1 : 0).join('')

  // solution 3 (with ASCII code)
  const upperCaseCodes = [65, 90] // ASCII codes for A-Z chars
  return [...str].sort((a,b) => inRange(a.charCodeAt(), ...upperCaseCodes) ? -1 : !inRange(b.charCodeAt(), ...upperCaseCodes) ? 1 : 0).join('')
 }

 console.log(sortStr('hApPy')) // "APhpy"