Write a function which takes a ROT13 encoded string as input and returns a decoded string. All letters will be uppercase. Do not transform any non-alphabetic character (i.e. spaces, punctuation), but do pass them on.

Caesars-Cipher.js

function rot13(str) {
  const splitStr = str.split('')
  let finalArr = []
  for(let i = 0; i < splitStr.length; i++){
    for(let j = 0; j < splitStr[i].split('').length; j++){
      
      const currentValueCode 
      = splitStr[i]
      .split('')[j]
      .charCodeAt()

      if(currentValueCode < 65 || currentValueCode > 90 ) finalArr.push(currentValueCode)

      else if(currentValueCode < 78) finalArr.push(currentValueCode + 13)
      
      else finalArr.push(currentValueCode - 13)
    }
  }
  return  String.fromCharCode(...finalArr)
}

console.log(rot13("SERR CVMMN!")); \\ FREE PIZZA!
console.log(rot13("SERR PBQR PNZC")); \\ FREE CODE CAMP