Hello,

Somebody asked me how I came up with the "versioning concept" in Valtio. Versioning is an important concept in Valtio, but it's not well known. It's considered an internal implementation detail, but we actually have a public API called getVersion. The version number is attached to a proxy object and it is incremented when the proxy object is changed. We use the version number to see if a snapshot (an immutable object) should be re-created. It's 100% optimized and the snapshot is only created when necessary. I introduced the versioning system so that we can create snapshots lazily. How did I come up with the idea? There was an insight. Originally, before I developed Valtio, I was experimenting with the idea, and back then, I used unstable_createMutableStore to integrate with React. It's an experimental React feature, and it requires a "version". This version can be anything, like an immutable object, but using a number makes sense to avoid garbage collection and it enables lazy snapshot creation. There are more background stories for Valtio, but specifically for "versioning", it was born to make mutable state usable in React through the experimental API in React.

You can find it in the initial commit of Valtio: https://github.com/pmndrs/valtio/commit/b4342250d1767ae02d0e5b81b5e99c84ae4acf86

Happy Hacking.

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