add support for branded types [closes #72]

Author: JanTvrdik

package-lock.json

@@ -0,0 +1,13 @@
+import { z } from 'zod';
+import { expectSchema, registerSchema } from '../lib/helpers';
+
+describe('branded', () => {
+  it('generates OpenAPI schema for branded type', () => {
+    expectSchema(
+      [registerSchema('SimpleStringBranded', z.string().brand<'color'>())],
+      {
+        SimpleStringBranded: { type: 'string' },
+      }
+    );
+  });
+});

spec/modifiers/branded.spec.ts

@@ -3,6 +3,7 @@ import type { z } from 'zod';
 type ZodTypes = {
   ZodArray: z.ZodArray<any>;
   ZodBoolean: z.ZodBoolean;
+  ZodBranded: z.ZodBranded<any, any>;
   ZodDefault: z.ZodDefault<any>;
   ZodEffects: z.ZodEffects<any>;
   ZodEnum: z.ZodEnum<any>;

src/lib/zod-is-type.ts

@@ -1003,7 +1003,11 @@ export class OpenAPIGenerator {
   }
 
   private unwrapChained(schema: ZodSchema<any>): ZodSchema<any> {
-    if (isZodType(schema, 'ZodOptional') || isZodType(schema, 'ZodNullable')) {
+    if (
+      isZodType(schema, 'ZodOptional') ||
+      isZodType(schema, 'ZodNullable') ||
+      isZodType(schema, 'ZodBranded')
+    ) {
       return this.unwrapChained(schema.unwrap());
     }