export function scrollTop(el: any, from = 0, to: number, duration = 500, endCallback?: Function) {
    if (!window.requestAnimationFrame) {
        window.requestAnimationFrame = (
            function (callback) {
                return window.setTimeout(callback, 1000/60);
            }
        );
    }
    const difference = Math.abs(from - to);
    const step = Math.ceil(difference / duration * 50);

    function scroll(start: number, end: number, step: number) {
        if (start === end) {
            endCallback && endCallback();
            return;
        }

        let d = (start + step > end) ? end : start + step;
        if (start > end) {
            d = (start - step < end) ? end : start - step;
        }

        if (el === window) {
            window.scrollTo(d, d);
        } else {
            el.scrollTop = d;
        }
        window.requestAnimationFrame(() => scroll(d, end, step));
    }
    scroll(from, to, step);
}