Javascript cifrado de cesar en

javascript_cesar_cipher.js

const abcValues = [
  "A",
  "B",
  "C",
  "D",
  "E",
  "F",
  "G",
  "H",
  "I",
  "J",
  "K",
  "L",
  "M",
  "N",
  "O",
  "P",
  "Q",
  "R",
  "S",
  "T",
  "U",
  "V",
  "W",
  "X",
  "Y",
  "Z"
]
function isAlpha(str) {
  return /^[a-zA-Z()]+$/.test(str);
}

function movePosition(position) {
  position += 13;
  if (position >= 26) {
    position -= 26;
  }
  return position;
}

function rot13(str) {
  const arrStr = str.split('')
  const arrCipher = arrStr.map(char => {
    if (isAlpha(char)) {
      let position = abcValues.indexOf(char);
      position = movePosition(position);
      return abcValues[position];
    }
    return char;
  });
  return arrCipher.join("");
}


console.log(rot13("SERR PBQR PNZC"));
/** * rot13("SERR PBQR PNZC") debe decodificarse en la cadena FREE CODE CAMP */