selectOption(list, selectedOption) {
    const options = list.querySelectorAll('li')
    // --Fix for IE11
    for (let i = 0; i < options.length; i++) {
      options[i].classList.remove('active-option')
    }
    if (selectedOption) {
      selectedOption.classList.add('active-option')
    }
  }
Selects option in autocomplete list. Removes class 'active-option' from all options
and then adds that class to 'selected' option. If 'selected' is null then no option is selected
@param {Object} list - list of autocomplete options
@param {Object} selectedOption - option - 'li' element - to be selected in autocomplete list