withTransaction

withTransaction<T>(pool: pg.Pool, fn: (client: pg.PoolClient) => Promise<T>): Promise<T>

Like withClient, but wraps the callback in a transaction.

• On success: COMMIT.
• On throw: ROLLBACK, then rethrow the original error — the rollback never masks it.
• If the ROLLBACK itself fails (usually a broken connection): the connection is destroyed rather than returned to the pool, so a poisoned connection is never handed to the next caller.

import connect, { withTransaction } from '@smplcty/db';

const pool = connect();

await withTransaction(pool, async (client) => {
  await client.query('insert into widgets (name) values ($1)', [name]);
  await client.query('update counters set n = n + 1 where k = $1', ['widgets']);
});

RLS-agnostic by design

withTransaction sets no session variables. Layer session/tenant GUCs inside the callback so services with different RLS conventions can share the same wrapper:

await withTransaction(pool, async (client) => {
  await client.query("select set_config('app.tenant_id', $1, true)", [id]);
  return client.query('select * from widgets'); // RLS now applies
});

This is the seam higher-level helpers (such as @smplcty/auth’s withSession) build on.