const regex = /(00|11|22|33|44|55|66|77|88|99)/;

let num = 3298;

num = num + 1;

let aux = (num).toString();

​

while (regex.test(aux)) {

  num += 1;

  aux = num.toString();

}

​

let num = 3298;

const consecutiveChars = function(num) {

  const arr = num.toString().split('');

  for (let idx = 0; idx < arr.length - 1; idx++) {

    if (arr[idx] == arr[idx + 1])

      return true;

  }

​

  return false;

}

​

num = num + 1;

while (consecutiveChars(num)) {

  num++;

}

​