getNextActiveElement = (list, activeElement, shouldGetNext, isCycleAllowed) => {
    const listLength = list.length;
    let index = list.indexOf(activeElement);

    // if the element does not exist in the list return an element
    // depending on the direction and if cycle is allowed
    if (index === -1) {
      return !shouldGetNext && isCycleAllowed ? list[listLength - 1] : list[0];
    }
    index += shouldGetNext ? 1 : -1;
    if (isCycleAllowed) {
      index = (index + listLength) % listLength;
    }
    return list[Math.max(0, Math.min(index, listLength - 1))];
  }
Return the previous/next element of a list.

@param {array} list    The list of elements
@param activeElement   The active element
@param shouldGetNext   Choose to get next or previous element
@param isCycleAllowed
@return {Element|elem} The proper element