[feature] Auto scroll like react-beautiful-dnd

[developerruhul]

Summary

• What is the feature?

This is a beautiful library with so many features but there's one part of this library that is really really poorly handled and that is the auto-scroll. Currently, the auto-scroll feels like it barely works. Sometimes it lags when the container is fixed and has 100vh height or there's some margin between items etc(live codesandbox). I'm working on an app that needs a smooth scroll similar to how it works in react-beautiful-dnd. It starts scrolling slowly when you go close to the edge and it speeds up as you go even closer to the edge. It feels so natural.

Here's how we want it to work and then how sortablejs currently works

react-beautiful-dnd

sortablejs

• Why is having this feature important to you?

I moved from react-beautiful-dnd to sortablejs because it doesn't support a tree-like nested list. But the auto-scroll of sortablejs just isn't something we can deploy to users because it feels so buggy that it feels like it barely works and it makes the whole UX looks so bad. So I'm literally stuck like many users of sortablejs who submitted issues regarding the auto-scroll.

• Who else will find having this feature helpful?

Literally everyone. This kind of smooth scroll is so natural that pretty much everyone wants it. I've seen so many issues in this repo about how auto-scroll isn't working, not responding to options etc. The auto-scroll indeed needs improvement.

here's a clean and simple codesandbox to test the scroll.

https://codesandbox.io/s/vanilla-sortablejs-scroll-test-fmch4

[developerruhul]

#1907 asks for a similar feature