this is great - i implemented something similar in a recent project, where we have some state being persisted "at the edge" (in cloudflare workers' key-value store product, workers kv) and cached in-browser using local storage. we wrote a bit about it here[1], though our approach[2] has changed a bit even since this post went out.

instead of directly interfacing with window.localStorage, we opted to use lscache[3], which allows us to expire keys: `lscache.set(key, value, 5)` (expires in 5 minutes)

[1]: https://blog.cloudflare.com/jamstack-at-the-edge-how-we-buil... [2]: https://github.com/cloudflare/workers.cloudflare.com/blob/ma... [3]: https://github.com/pamelafox/lscache