Look at using CSS scroll-behavior

[masonhale]

Smooth scrolling behavior is being baked into browsers.
Consider using a polyfill to leverage that behavior.

See:

• https://github.com/iamdustan/smoothscroll
• https://developer.mozilla.org/en/docs/Web/CSS/scroll-behavior
• https://news.ycombinator.com/item?id=13920512