J vltasl rlhr zdfog odxr ypw atasl rlhr p gwkzzyq zntyhv lvz wp!!!

I sho;ld ha<e k45=4 :.a: ?5; =5;2* .a<+ a 6+8,+): a49=+8 ,58 3+!!!

function demovingShift(v, shift) {
  shift = -1;
  let str = v.join("");
  let arr = [];
  let alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split("");
  str.split("").forEach((x, idx) => {
  if (shift === -27) {
    shift = -1;
  }
  let source = x.toUpperCase().charCodeAt(0);
  if (source < 65 || source > 90) {
    arr.push(x);
    shift--;
    return;
  }
  let index = alphabet.indexOf(x.toUpperCase());
  let letter = alphabet.slice(index + shift, index + shift + 1).toString();
  x === x.toLowerCase() ? arr.push(letter.toLowerCase()) : arr.push(letter);
            shift--;
  })
    return arr.join("");