Strange unexpected delay before mouseleave animation

I'm currently trying to create a little animation when hovering a div using .animate() jQuery function.

If you take a look at the code snippet, you will see that there is a very strange delay between the time your mouse leave the div and the animation is launch.

It's definitely something with .animate() function because, there is a console.log that is displayed when the mouse leave the div and without any strange delay.

Did I miss something or... Any ideas will be appreciate!

Thanks!

$(document).ready(function() {
  $(".square").hover(function() {
      var _this = this;
      $(_this).find(".square-hover").eq(0).animate({
        top: "0px",
      }, 750)
    })
    $(".square").mouseleave(function() {
      var _this = this;
      console.log("mouseleave triggered");
      $(_this).find(".square-hover").eq(0).animate({
        top: "-300px",
      }, 100)
    });
})

.square {
  box-shadow: 0 2px 2px 0 rgba(0,0,0,0.14), 0 1px 5px 0 rgba(0,0,0,0.12), 0 3px 1px -2px rgba(0,0,0,0.2);
  padding: 0;
  border: 1px solid rgba(255, 255, 255, 0.1);
  height: 200px;
  -webkit-transition-property: background-color;
  -webkit-transition-duration: 0.2s;
  overflow: hidden;
  margin-top: 5px
}

.square-hover{
  position: absolute;
  top: -300px;
  width: 100%;
  height: 100%;
  background-color: rgba(29, 233, 182, 0.85);
}

<script src="http://code.jquery.com/ui/1.12.0/jquery-ui.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>
<div class="col-xs-6 col-xs-offset-3 square">
  <div class="square-hover"></div>
</div>

Solution

The issue is because you're using hover and mouseleave. The hover event handler is actually separate mouseenter and mouseleave handlers - so you're actually attaching 1 mouseenter and 2 mouseleave. This is the cause of your issue.

If you change the code to pass two functions to hover (the first for mouseenter, second for mouseleave) your code works:

$(".square").hover(function() {
    $(this).find(".square-hover").eq(0).stop(true).animate({
        top: "0px",
    }, 750)
}, function() {
    $(this).find(".square-hover").eq(0).stop(true).animate({
        top: "-300px",
    }, 100)
});

Updated fiddle

Also note the use of stop(true) in the above to prevent successive events clogging up the animation queue.