Comsequent

$(function() {
    // create an empty variable
    var selectedClass = "";
    // call function when item is clicked
    $(".lastest-work__nav-link").click(function(){
      // assigns class to selected item
      selectedClass = $(this).attr("data-rel");
      // hide all portfolio items
      $(".demonstration-lastest-work .demonstration-lastest-work__inner").fadeOut(300);
      // show selected category
      if(selectedClass==='all'){
        $(".demonstration-lastest-work__inner").delay(300).fadeIn(300);
      } else {
        $("." + selectedClass).delay(300).fadeIn(300);
      }
    });
  });