Local storage

WatermelonDB has a simple key/value store, similar to localStorage:

// setting a value
await database.localStorage.set("user_id", "abcdef")

// retrieving a value
const userId = await database.localStorage.get("user_id") // string or undefined if no value for this key

// removing a value
await database.localStorage.remove("user_id")

When to use it. For things like the ID of the logged-in user, or the route to the last-viewed screen in the app. You should generally avoid it and stick to standard Watermelon records.

This is a low-level API. You can't do things like observe changes of a value over time. If you need that, just use standard WatermelonDB records. You can only store JSON-serializable values

What to be aware of. DO NOT let the local storage key be a user-supplied value. Only allow predefined/whitelisted keys. Key names starting with __ are reserved for WatermelonDB use (e.g. used by Sync to remember time of last sync)

Why not use localStorage/AsyncStorage? Because this way, you have only one source of truth — one database that, say, stores the logged-in user ID and the information about all users. So there's a lower risk that the two sets of values get out of sync.