Sqlite3 WebAssembly
https://sqlite.org/wasm/doc/trunk/index.mdThen on subsequent visits use that server-side data to rehydrate the client-side database.
From https://sqlite.org/forum/info/50a4bfdb294333eec1ba4749661934... is looks like WAL mode is excluded from the default SQLite WASM build so you would have to go custom with that.
In-memory SQLite databases don't use WAL. Wasm (and browser Wasm, in particular) doesn't support anything like the shared memory APIs SQLite wants for its WAL mode.
Litestream requires a very precise WAL setup to work (which just so happens to work with the default native SQLite setup, but is hard to replicate with Wasm).
Cloudflare Durable Objects may have been inspired by Litestream but works very differently (as do LiteFS, Turso, etc…)
The general idea of streaming changes from SQLite would work, but it's a lot of work, and the concurrency model of in-browser Wasm will make it challenging to implement.
(I wrote that forum post some time ago, and have WAL working in a server side Wasm build of SQLite, but none of the options to make it work would make much sense, or be possible, in browser)
I'm gathering that I need to learn about: - WAL - Shared Memory APIs - Concurrency models - Durable Objects?
Shared memory API: If you want to share (mutable) data between multiple processes, you need some kind of procedure in place to manage that. How do you get a reference to the data to multiple processes, how do you make sure they don't trample each other's writes, etc.
Concurrency model: There are many different ways you can formalize concurrent processes and the way they interact (message passing, locking, memory ordering semantics, etc.). Different platforms will expose different concurrency primitives that may not work the same way as other platforms and may require different reasoning or code structure
Durable objects - I think this is some Cloudflare service where they host data that can be read or modified by your users
This is all from memory, but IME, GPT is pretty good for asking about concepts at this level of abstraction
And side note on your last point - I've been burned too many times by confident hallucinations to trust my foundational learning to GPT. I hope someday that will improve, but for now ChatGPT is as trustworthy as an evening chat with someone at the bar.
... Someone who has been drinking since happy hour.
> These components were initially released for public beta with version 3.40 and will tentatively be made API-stable with the 3.41 release, pending community feedback.
But the most recent release of SQLite is 3.46.1 (from 2024-08-13)
Presumably they are now "API-stable" but the page hasn't been updated yet.
It would be great if the SQLite team published an official npm package bundling the WASM version, could be a neat distribution mechanism for them.
My favourite version of SQLite-in-WASM remains the Pyodide variant, which has been around since long before the official SQLite implementation. If you use Pyodide you get a WASM SQLite for free as part of the Python standard library - I use that for https://lite.datasette.io/ and you can also try it out on https://pyodide.org/en/stable/console.html
import sqlite3
print(sqlite3.connect(':memory:').execute(
'select sqlite_version()'
).fetchall())
sqlite-wasm loads much faster than Pyodide, so if you don't need Python, then the former is a better choice.
npm install @sqlite.org/sqlite-wasmWith the help of Claude, though it incorrectly hallucinated some of the details despite me pasting in documentation: https://gist.github.com/simonw/677c3794051c4dfeac94e514a8e5b...
For an in-browser app, that seems a bit much but of course wasm runs in other places these days where it might make more sense.
Also worth considering parsing of wasm is significantly faster than JS (unfortunately couldn't find the source for this claim, there is at lease one great article on the topic)
https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_A...
Meanwhile for “local-only” it would be great to use sqlite in the browser + native file system API so that the db could be stored on the user’s file system and we wouldn’t have to worry about browser storage eviction. i think that could really open up a whole world of privacy preserving offline software delivered through the browser