JS stiky header implementation

stikyHeader.js

var mobileBreackpoint = 767;

var stickyElem = $('.page-header');
var stickyElemCheckpoint = 82;
var stickyElemActiveClass = 'page-header_sticky';
var stickyElemHelperClass = 'page-header_inert-sticky';

stickyElem.addClass(stickyElemHelperClass);

$(document).ready(function() {
    updateSticky();
    $(window).scroll(function() {
        updateSticky();
    });
    $(window).resize(function() {
        updateSticky();
    });
});

function updateSticky() {
    var currentScrollPosition = $(window).scrollTop();

    if (window.innerWidth <= mobileBreackpoint) { // if mobile
        stickyElem.addClass(stickyElemActiveClass);
        document.body.style.paddingTop = stickyElem.outerHeight(true) + "px"; // true - includeMargin
    }

    if (window.innerWidth > mobileBreackpoint) { //if desktop
        if (currentScrollPosition > stickyElemCheckpoint) {
            compensateInitialSize();
            // stickyElem.addClass(stickyElemActiveClass);
        }
        if (currentScrollPosition <= stickyElemCheckpoint) {
            compensateInitialSize();
        }
    }
}

function compensateInitialSize() {
    stickyElem.removeClass(stickyElemActiveClass);
    document.body.style.paddingTop = stickyElem.outerHeight(true) + "px"; // true - includeMargin
}