nurl/public/javascripts/shorten.js

$('#btn-shorten').on('click', function(){
  $.ajax({
    url: '/api/v1/shorten',
    type: 'POST',
    dataType: 'JSON',
    data: {url: $('#url-field').val()},
    success: function(data){
        const $link = $('#link');
        const resultHTML = `<a class="result" href="${data.shortUrl}">${data.shortUrl}</a>`;
        $link.html(resultHTML);
        $link.hide().fadeIn('slow');
    }
  });

});