Here is the logic of infinite scroll from the top to the bottom of the screen :

height = function (elem) {
    elem = elem[0] || elem;
    if (isNaN(elem.offsetHeight)) {
        return elem.document.documentElement.clientHeight;
    } else {
        return elem.offsetHeight;
    }
};
offsetTop = function (elem) {
    if (!elem[0].getBoundingClientRect || elem.css('none')) {
        return;
    }
    return elem[0].getBoundingClientRect().top + pageYOffset(elem);
};
pageYOffset = function (elem) {
    elem = elem[0] || elem;
    if (isNaN(window.pageYOffset)) {
        return elem.document.documentElement.scrollTop;
    } else {
        return elem.ownerDocument.defaultView.pageYOffset;
    }
}
handler = function () {
    if (container === windowElement) {
        containerBottom = height(container) + pageYOffset(container[0].document.documentElement);
        console.log('height(elem', height(elem))
        elementBottom = offsetTop(elem) + height(elem);
    } else {
        containerBottom = height(container);
        containerTopOffset = 0;
        if (offsetTop(container) !== void 0) {
            containerTopOffset = offsetTop(container);
        }
        elementBottom = offsetTop(elem) - containerTopOffset + height(elem);
    }
    if (useDocumentBottom) {
        elementBottom = height((elem[0].ownerDocument || elem[0].document).documentElement);
    }
    remaining = elementBottom - containerBottom;
    shouldScroll = remaining <= height(container) * scrollDistance + 1;
}

How can I modify my code in order to infinite scroll properly from the bottom to the top of the screen.

I try to do this, i change the hendler function i remove all my code and I do this

elemenTop = pageYOffset(container[0].document.documentElement)
remaining = elemenTop - 250;
shouldScroll = remaining <= height(container) * scrollDistance + 1;

When u test infinite scroll module. if u want to use the scroll bar to go directly to the bottom of the screen it keeps loading the data till u have no data to load.With my modification when I go straight to the top of the screen with the scroll bar it doesn't keep loading my data, it stops to load the data and i have to scroll to make it work again.

I shouldn't have to scroll to make it work again when i'm in the top it should scroll itself since I have all the data loaded