Ajax.js

// ajax filtering
$('.cat-list_item').on('click', function(e) {
    e.preventDefault();
    $('.cat-list_item').removeClass('active');
    $(this).addClass('active');

    $.ajax({
      type: 'POST',
      url: '/wp-admin/admin-ajax.php',
      dataType: 'json',
      data: {
        action: 'filter_projects',
        category: $(this).data('slug'),
      },
      success: function(res) {
        currentPage = 1;
        $('.post-filter').html(res.html);
        $('.card').each(function(i) {
          // 'i' stands for index of each element
          $(this).delay(i * 400).fadeIn(600);
        });
      }
    })

  });

  // ajax load more
  let currentPage = 1;
  $('#load-more').on('click', function() {
    currentPage++;

    $.ajax({
      type: 'POST',
      url: '/wp-admin/admin-ajax.php',
      dataType: 'json',
      data: {
        action: 'load_more_projects',
        category: $(this).data('slug'),
        paged: currentPage,
      },
      success: function (res) {
        if(currentPage >= res.max) {
          $('#load-more').hide();
        }
        $('.post-filter').append(res.html);
      }
    });
  });