From 7769b641d8bdf622c84380a5bb8c3dbfa6504f56 Mon Sep 17 00:00:00 2001
From: Nubami SQReder <sqreder@gmail.com>
Date: Wed, 4 Sep 2024 08:38:15 +0300
Subject: [PATCH] fix/zod contracts lose branding (#513)
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* fix: #511 use type inference from zod in zodContract

* fix zodContracts output type inference

* fix: Import missing type

* Update quick-adults-punch.md

* Format

---------

Co-authored-by: Igor Kamyşev <igor@kamyshev.me>
---
 .changeset/quick-adults-punch.md              |  5 +++++
 packages/zod/src/__tests__/contract.test-d.ts | 13 +++++++++++++
 packages/zod/src/zod_contract.ts              |  8 +++++---
 3 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/quick-adults-punch.md

diff --git a/.changeset/quick-adults-punch.md b/.changeset/quick-adults-punch.md
new file mode 100644
index 000000000..7a175d1a4
--- /dev/null
+++ b/.changeset/quick-adults-punch.md
@@ -0,0 +1,5 @@
+---
+"@farfetched/zod": patch
+---
+
+Fix `zodContracts` type inference for branded types
diff --git a/packages/zod/src/__tests__/contract.test-d.ts b/packages/zod/src/__tests__/contract.test-d.ts
index 813e9f937..c9d3b854e 100644
--- a/packages/zod/src/__tests__/contract.test-d.ts
+++ b/packages/zod/src/__tests__/contract.test-d.ts
@@ -58,4 +58,17 @@ describe('zodContract', () => {
       >();
     }
   });
+
+  test('branded type', () => {
+    const BrandedContainer = zod.object({
+      branded: zod.string().brand<'Branded'>(),
+    });
+    const brandedContract = zodContract(BrandedContainer);
+
+    const smth: unknown = { branded: 'branded' };
+
+    if (brandedContract.isData(smth)) {
+      expectTypeOf(smth).toEqualTypeOf<zod.infer<typeof BrandedContainer>>();
+    }
+  });
 });
diff --git a/packages/zod/src/zod_contract.ts b/packages/zod/src/zod_contract.ts
index 4006555f3..7e69a9956 100644
--- a/packages/zod/src/zod_contract.ts
+++ b/packages/zod/src/zod_contract.ts
@@ -1,4 +1,4 @@
-import { type ZodType } from 'zod';
+import { type ZodType, type TypeOf } from 'zod';
 import { type Contract } from '@farfetched/core';
 
 /**
@@ -7,8 +7,10 @@ import { type Contract } from '@farfetched/core';
  *
  * @param {ZodType} data Zod Contract for valid data
  */
-function zodContract<D>(data: ZodType<D>): Contract<unknown, D> {
-  function isData(prepared: unknown): prepared is D {
+function zodContract<T extends ZodType<any, any, any>>(
+  data: T
+): Contract<unknown, TypeOf<T>> {
+  function isData(prepared: unknown): prepared is T {
     return data.safeParse(prepared).success;
   }