Am I doing something wrong?

[darklight9811]

I'm trying to make this work but its not reactive:
https://stackblitz.com/edit/vitejs-vite-ugxwsd

[jmeistrich]

Hi @darklight9811, sorry for the delay! I wasn't getting notified for discussions, hopefully fixed now...

It looks like the way you're pushing to the array is the problem:

onClick={(e) => {
    points.set((prev) => {
        prev.push([e.pageX, e.pageY]);

        return prev;
    });
}}

This pushes to the underling array instead of the observable, so it doesn't notify observers that it's changed. You can just push to the observable array.

onClick={(e) => {
    points.push([e.pageX, e.pageY]);
}}

Legend-State data is mutable which works a bit differently than normal React hooks which require immutables. We have a section on the docs about that: https://legendapp.com/open-source/state/v3/usage/observable/#observables-are-mutable