From 6e73af03830c576ff764c84b863a79cd0eb35a8c Mon Sep 17 00:00:00 2001
From: Harjot Singh <harjotsrance@gmail.com>
Date: Sun, 14 Jun 2026 01:18:03 +0530
Subject: [PATCH] fix(types): type pg Client as the constructor (typeof
 Pg.Client)

The plugin assigns `pg.Client` (the class) to `app.pg.Client` at runtime,
but the `PostgresDb` type declared it as `Pg.Client` (an instance). This made
`new app.pg.Client(...)` fail to type-check with TS2351 "This expression is not
constructable" even though it works at runtime.

Type the member as `typeof Pg.Client` so it reflects the constructor, and update
the type test to assert against `typeof Client`.

Signed-off-by: Harjot Singh <harjotsrance@gmail.com>
---
 index.d.ts              | 2 +-
 test-types/query.tst.ts | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/index.d.ts b/index.d.ts
index 4516b96..92fee34 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -20,7 +20,7 @@ type FastifyPostgres = FastifyPluginCallback<fastifyPostgres.PostgresPluginOptio
 declare namespace fastifyPostgres {
   export type PostgresDb = {
     pool: Pg.Pool;
-    Client: Pg.Client;
+    Client: typeof Pg.Client;
     query: Pg.Pool['query'];
     connect: Pg.Pool['connect'];
     transact: typeof transact;
diff --git a/test-types/query.tst.ts b/test-types/query.tst.ts
index 2e172b4..68ab9bf 100644
--- a/test-types/query.tst.ts
+++ b/test-types/query.tst.ts
@@ -13,7 +13,7 @@ app.get('/calc', async () => {
   expect(app.pg).type.toBeAssignableTo<PostgresDb>()
 
   expect(app.pg.pool).type.toBe<Pool>()
-  expect(app.pg.Client).type.toBe<Client>()
+  expect(app.pg.Client).type.toBe<typeof Client>()
 
   const client = await app.pg.connect()
   expect(client).type.toBe<PoolClient>()