I write Bun.sql with raw SQL and no ORM, and the one thing I kept missing was types. You write a query, get back `any[]`, and hand-write a row type that silently drifts from the actual columns. Drizzle/Kysely fix this by moving the query into TypeScript, but then you're not really writing SQL anymore.
bun-sqlgen goes the other way. You keep writing raw SQL queries, just give each one a name.
A codegen step reads your migration `.sql` files, stands up a throwaway Postgres via PGlite (so no Docker) or SQLite, prepares every tagged query against it, and writes a `.d.ts` that maps each query name to its real result type. After that, plain `tsc` does the rest: `user.notExistingField` won't compile, and `display_name.length` gets flagged because the column is nullable.
Nullability was the annoying part. Postgres's describe doesn't hand you per-column nullability, so I infer it from the query plan plus the catalog, with manual overrides for the cases that genuinely can't be inferred. SQLite works too.
The runtime stays 100% Bun.sql, the generated file is the only artifact (commit it), and codegen is fast enough to rerun on save.
It's early (v0.1, built it for my own projects) so I'd mostly like to hear where it falls over.
Can you describe how it's the same and how it's different than SQLx (a Rust thing)?
I actually took a lot of inspiration from sqlx, which is really nice. The main differences are:
- in JS/TS you don't have compile-time scripts that you can run like with Rust's macros, so you need to run a codegen command before running the type checks (disadvantage)
- I had to create a TS parser that goes and finds the tagged template functions with the sql statements, while sqlx has them "for free" because sql statements are the input to the macro itself (disadvantage)
- I use an in-memory Postgres (PGLite) to describe the queries, instead of requiring a running pg instance (advantage)
- I don't cache the statements and codegen for now like sqlx does, something that can be added later
I think they are similar in that they both substitute the dynamic params with no-ops like $1, $2, etc. before handing the sql statement to the pg's DESCRIBE function
Very interesting! I spent a long session in a harness the other day getting pglite to the point it would work reliably in a browser for a specific use case I had. The key was NOT using that environment to run the SQLx validation, but just having a real long running Postgres for local builds + CI, and simply creating and dropping a database for that run.
Used pglite-oxide for the Electron build and then we went off into the weeds and ported pglite so it could run in iOS for iOS apps. The easiest way to do this is to just do it as a plain old Mac app first and get it working there first.
I’ll open source this if I figure out if we can maintain it and document it.
> silently drifts
> genuinely
> I'd mostly like to hear where it falls over.
https://news.ycombinator.com/newsguidelines.html#generated