JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main"></div>
<footer class="nav-down">123</footer>

CSS

* {
    margin:0;
    padding:0;
    color: transparent;
}
.main {
    width:100%;
    height:1500px;
}
.nav-down {
    bottom: -40px;
}
footer {
    -webkit-backface-visibility: hidden;
    background: #000;
    height: 40px;
    position: fixed;
    bottom: 0;
    transition: bottom 0.2s ease-in-out;
    width: 100%;
    z-index: 1000;
    border-top:1px solid #000;
}

JavaScript

// Hide Footer on on scroll down
var didScroll;
var lastScrollTop = 0;
var delta = 5;
var navbarHeight = $('footer').outerHeight();


function IsBottom() {
    return $(window).scrollTop() == ($(document).height() - $(window).height());
}

$(window).scroll(function (event) {
    didScroll = true;
    if (IsBottom()) {
        $('footer').removeClass('nav-down').addClass('nav-up');
    }
});

setInterval(function () {
    if (didScroll && !IsBottom()) {
        hasScrolled();
        didScroll = false;
    }
}, 250);

function hasScrolled() {
    var st = $(this).scrollTop();

    // Make sure they scroll more than delta
    if (Math.abs(lastScrollTop - st) <= delta) return;

    if (st > lastScrollTop && st > navbarHeight) {

        $('footer').removeClass('nav-up').addClass('nav-down');
    } else {

        if (st + $(window).height() < $(document).height()) {
            $('footer').removeClass('nav-down').addClass('nav-up');
        }
    }

    lastScrollTop = st;
};