Yes you're right. Accessing IndexedDB from WebAssembly needs to go through JavaScript. The only benefit from our perspective is that building it in Rust enables us to use the same logic and code that powers our entire database platform. From a performance aspect, you're right, it still needs to go through JavaScript.

So we don't use any features from IndexedDB at all really. We literally treat IndexedDB as a key-value store interface like RocksDB or something like that. So all of the indexing is done within SurrealDB, and is stored in IndexedDB as a set of binary keys->values (Uint8Array if I remember correctly).

When we want to query a whole table, or a subset of a table, SurrealDB determines what individual keys to load or what key ranges need to be loaded to perform the query.

Would love to chat further about this - it's a really interesting area of discussion for me!