Why drizzle db.query.<tbl>.findFirst does not return an optional value?

[s1n7ax]

I picked drizzle orm considering it's strong type safety and just realized db.query.<tbl>.findFirst does not return an optional value while at runtime I can get undefined without error out. Is there a way to fix typing or do I have to manually type every repository function I have to include Promise<ExpType | undefined>?

[everton-dgn]

On recent Drizzle (drizzle-orm@0.30+), db.query.<tbl>.findFirst() already returns Promise<T | undefined> and TypeScript flags any unchecked field access:

const post = await db.query.posts.findFirst();
// type: typeof posts.$inferSelect | undefined

post.title; // TS: 'post' is possibly 'undefined'

if (post) {
  post.title; // safe
}

If you're seeing Promise<T> without the | undefined, you're on an older version where this was a typing bug — it was fixed in the 0.30 line. Upgrading resolves it:

pnpm update drizzle-orm

Temporary cast if you can't upgrade yet:

const post = await db.query.posts.findFirst() as typeof posts.$inferSelect | undefined;

Or an explicit signature on your repo functions so callers see the right type regardless of the underlying version:

async function getPost(id: number): Promise<typeof posts.$inferSelect | undefined> {
  return db.query.posts.findFirst({ where: eq(posts.id, id) });
}

Side note: when a where clause is guaranteed to match (e.g., primary key lookup) and you'd rather throw than branch on undefined, Drizzle doesn't ship a findFirstOrThrow like Prisma does, but it's a 3-line helper to write.