This is a fascinating find, well and truly. I don’t know the answer 100% but I know it will hinge on one question:
Can emcc compile LiteCore?
I’m unaware of its capabilities, limitations, or modern C++ support (or if it even compiles C++ at all) but if the answer is yes, then I’d say that pretty much assures that CBL will run in Blazor. Traditionally the thing that kept this from happening is the extreme limitation on I/O (both networked and disk) inside of WebAssembly. Basically without network I/O and proper disk I/O CBL is pretty moot.
The problem with SQLite in WASM is that WASM doesn’t have a filesystem API, because web apps don’t have access to the filesystem. I did hear of an epic hack where somebody got around this by implementing a SQLite virtual filesystem plugin that stores files in a row of an IndexedDB. This is probably not very scalable.
The big showstopper for Couchbase Lite in WASM is that (last I heard) WASM doesn’t yet support threads.
I did think it all sounded too easy to be honest. It does give me hope that the holy grail might be achievable in the near future though. It would be pretty cool to have a single wasm app that could utilise CBL’s amazing sync feature and deploy it in a web browser as well.