text: let phrase = null;
  while (phrase === null) {
    phrase = prompt(
      'enter something with duplicated letters, they will be removed'
    );
  }
  
  let previous = '';
  
  let noRepetitions = '';
  for (let next of phrase) {
    if (next !== previous) {
      noRepetitions = noRepetitions + next;
    }
    previous = next;
  }
  
  alert(noRepetitions);
  