function generateAuthors() {
    let allAuthors = {};
    const authorsList = document.querySelector(optAuthorsListSelector);
    const films = document.querySelectorAll(optFilmSelector);
    let html = '';

    for(let film of films){
        const author = film.getAttribute('data-author');

        if(!allAuthors.hasOwnProperty(author)){
          allAuthors[author] = 1;
        } else {
          allAuthors[author]++;
      }
    }

    for(let author in allAuthors){
      html += '<li><a href="#author-' + author + '">' + author + '</a></li>'
    }
    authorsList.innerHTML = html;

    const authors = document.querySelectorAll('.authors a')

    for(let author of authors){
      author.addEventListener('click', authorClickHandler);
    }

}