Smooth Native Scroll

smoothNativeScroll.js

smoothScroll = speed => {
  var endPos, comp, step;
  const goScroll = function goScroll() {
          scrollBy(0, step);
          if (comp(window.scrollY, endPos)) {
            window.requestAnimationFrame(goScroll);
          }
        },
        runner = end => {
          endPos = end;
          if (end > window.scrollY) {
            comp = _.lt;
            step = speed;
            window.requestAnimationFrame(goScroll);
          } else {
            comp = _.gt;
            step = 0 - speed;
            window.requestAnimationFrame(goScroll);
          }
        };

  return {
    by: by => runner(by + window.scrollY),
    to: runner
  };
};