Scroll events performance

didscroll.js

// Resource https://medium.com/@mariusc23/hide-header-on-scroll-down-show-on-scroll-up-67bbaae9a78c

var scrollValInit = 200;
var didScroll;

$(window).scroll(function () {
    didScroll = true;
});

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

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

    if ($scrollTopVal > scrollValInit) {
        $btnToTop.addClass('active');
    } else {
        $btnToTop.removeClass('active');
    }
}