function fooFunc() {

  const fooTl = new TimelineMax();

  fooTl
  .to($item,.5,{display:'none'})
  ;

  return fooTl;
}

TweenMax.to($item,.5,{display:'none'});

timelineTl.play();
timelineTl.pause();

timelineTl
.to($item,.5,{display:'none'})
.add(fooFunc())
;