From f5186910f9cc7bf7d1b94b5a0364ab67cbf18644 Mon Sep 17 00:00:00 2001
From: Julian Schleemann <julian.schleemann@atmina.de>
Date: Thu, 8 Feb 2024 18:52:25 +0100
Subject: [PATCH] feat: allow drilling through optional and nullable

---
 src/formbuilder.tsx |  4 +++-
 src/types.test.tsx  | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/formbuilder.tsx b/src/formbuilder.tsx
index 339930c..fbdd31b 100644
--- a/src/formbuilder.tsx
+++ b/src/formbuilder.tsx
@@ -81,7 +81,9 @@ export type FormBuilder<T> = FormBuilderRegisterFn<T> & {
         ): $UseFieldArrayReturn<TItem>;
       }
     : {
-        [K in Exclude<keyof T, `${"__"}${string}`>]-?: FormBuilder<T[K]>;
+        [K in Exclude<keyof T, `${"__"}${string}`>]-?: FormBuilder<
+          T[K] extends Primitive ? T[K] : NonNullable<T[K]>
+        >;
       });
 
 /*
diff --git a/src/types.test.tsx b/src/types.test.tsx
index 032be76..26bc99b 100644
--- a/src/types.test.tsx
+++ b/src/types.test.tsx
@@ -38,6 +38,14 @@ describe("Types", () => {
       FormBuilder<{ foo?: string }>
     >();
 
+    // Nested optional
+    type NestedOptional = FormBuilder<{
+      foo?: { bar?: { baz?: string } };
+    }>;
+    expectTypeOf<NestedOptional["foo"]["bar"]["baz"]>().toMatchTypeOf<
+      FormBuilder<string>
+    >();
+
     // Nullable
     expectTypeOf<FormBuilder<string | null>>().toMatchTypeOf<
       FormBuilder<string>
@@ -46,6 +54,14 @@ describe("Types", () => {
       FormBuilder<string | null>
     >();
 
+    // Nested nullable
+    type NestedNull = FormBuilder<{
+      foo: { bar: { baz: string | null } | null } | null;
+    }>;
+    expectTypeOf<NestedNull["foo"]["bar"]["baz"]>().toMatchTypeOf<
+      FormBuilder<string>
+    >();
+
     // Undefined
     expectTypeOf<FormBuilder<string | undefined>>().toMatchTypeOf<
       FormBuilder<string>