[kirillrogovoy]

While not 100% same thing, I've been a happy user of nanostores to manage state in vanilla JS.

It has `computed` too which works very similarly. On top of that, it has integrations with front-end frameworks such as React.

https://github.com/nanostores/nanostores

[FractalHQ]

These are Observables, as seen in Svelte and RXJS. When talking about reactivity primitives / patterns, Observables and Signals are two of the most common / prominent ones. So in this context, they are closer to being 100% different things.