function noDuplicates(arr) {
  let noDuplicatesArray = [];
  let previous = null;

  for (let i = 0; i < arr.length; i++) {
    let element = arr[i];
    if (previous === null) {
      noDuplicatesArray.push(element);
      previous = element;
      continue;
    }
    if (element === previous) {
      continue;
    }
    noDuplicatesArray.push(element);
    previous = element;
  }

  return noDuplicatesArray;
}