jQuery: eliminate white screen “pause” between animations

Question

I have just discovered Barba.js and find it very useful. It provides smooth transitions between URLs of the same website.

I have put together a

Answer 1

I came out with this version of the script:

$(function(){
    var transEffect = Barba.BaseTransition.extend({
    start: function() {
      this.newContainerLoading.then(val => this.fadeInNewcontent($(this.newContainer)));
    },
    fadeInNewcontent: function(nc) {
      var _this = this;
      nc.css('visibility', 'visible');
      nc.show().promise().done(() => {
        $(this.oldContainer).fadeOut(50);
        if (!isMobile.any()) {
          $('html, body').delay(100).animate({
            scrollTop: 200
          },700);
        }
      });
    }
  });
  Barba.Pjax.getTransition = function() {
    return transEffect;
  }
  Barba.Pjax.start();
});

It is better, but not smooth enough. See the the effect on a real life project. How can I improve it?