fix: correctly transform untyped nullable field to

Author: davejsdev

.changeset/large-ways-cheat.md

@@ -0,0 +1,5 @@
+---
+"openapi-typescript": patch
+---
+
+Correctly transform untyped nullable fields to `unknown`

packages/openapi-typescript/src/transform/schema-object.ts

@@ -267,7 +267,7 @@ export function defaultSchemaObjectTransform(schemaObject: SchemaObject | Refere
   }
 
   // nullable (3.0)
-  if (schemaObject.nullable) finalType = tsUnionOf(finalType || "Record<string, unknown>", "null");
+  if (schemaObject.nullable) finalType = tsUnionOf(finalType || "unknown", "null");
 
   if (finalType) return finalType;
 

packages/openapi-typescript/test/schema-object.test.ts

@@ -374,6 +374,11 @@ describe("Schema Object", () => {
       const generated = transformSchemaObject({}, options);
       expect(generated).toBe(`unknown`);
     });
+
+    test("unknown nullable", () => {
+      const generated = transformSchemaObject({ nullable: true }, options);
+      expect(generated).toBe(`unknown`);
+    });
   });
 
   describe("schema composition", () => {