fix(zod-openapi): support default response (#855)

* fix(zod-openapi): support default response

* chore: changeset

.changeset/curly-eagles-relate.md

@@ -0,0 +1,5 @@
+---
+'@hono/zod-openapi': patch
+---
+
+fix: support default response

packages/zod-openapi/src/index.ts

@@ -194,16 +194,26 @@ type RouteConfigStatusCode = keyof StatusCodeRangeDefinitions | StatusCode
 type ExtractStatusCode<T extends RouteConfigStatusCode> = T extends keyof StatusCodeRangeDefinitions
   ? StatusCodeRangeDefinitions[T]
   : T
-export type RouteConfigToTypedResponse<R extends RouteConfig> = {
+type DefinedStatusCodes<R extends RouteConfig> = keyof R['responses'] & RouteConfigStatusCode
-  [Status in keyof R['responses'] &
+export type RouteConfigToTypedResponse<R extends RouteConfig> =
-    RouteConfigStatusCode]: undefined extends R['responses'][Status]['content']
+  | {
+      [Status in DefinedStatusCodes<R>]: undefined extends R['responses'][Status]['content']
         ? TypedResponse<{}, ExtractStatusCode<Status>, string>
         : ReturnJsonOrTextOrResponse<
             keyof R['responses'][Status]['content'],
             ExtractContent<R['responses'][Status]['content']>,
             Status
           >
-}[keyof R['responses'] & RouteConfigStatusCode]
+    }[DefinedStatusCodes<R>]
+  | ('default' extends keyof R['responses']
+      ? undefined extends R['responses']['default']['content']
+        ? TypedResponse<{}, Exclude<StatusCode, ExtractStatusCode<DefinedStatusCodes<R>>>, string>
+        : ReturnJsonOrTextOrResponse<
+            keyof R['responses']['default']['content'],
+            ExtractContent<R['responses']['default']['content']>,
+            Exclude<StatusCode, ExtractStatusCode<DefinedStatusCodes<R>>>
+          >
+      : never)
 
 export type Hook<T, E extends Env, P extends string, R> = (
   result: { target: keyof ValidationTargets } & (

packages/zod-openapi/test/handler.test-d.ts

@@ -147,4 +147,86 @@ describe('supports async handler', () => {
     const hono = new OpenAPIHono()
     hono.openapi(route, handler)
   })
+
+  test('handler should support default response for unspecified status codes', () => {
+    const routeWithDefault = createRoute({
+      method: 'get',
+      path: '/users',
+      responses: {
+        200: {
+          content: {
+            'application/json': {
+              schema: z.object({ id: z.string() }),
+            },
+          },
+          description: 'Success response',
+        },
+        default: {
+          content: {
+            'application/json': {
+              schema: z.object({ error: z.string() }),
+            },
+          },
+          description: 'Error response',
+        },
+      },
+    })
+
+    const errorHandler: RouteHandler<typeof routeWithDefault> = (c) => {
+      return c.json({ error: 'Server Error' }, 500)
+    }
+
+    const hono = new OpenAPIHono()
+    hono.openapi(routeWithDefault, errorHandler)
+  })
+
+  test('handler should respect explicitly defined status codes with default fallback', () => {
+    const routeWithDefault = createRoute({
+      method: 'get',
+      path: '/users',
+      responses: {
+        200: {
+          content: {
+            'application/json': {
+              schema: z.object({ id: z.string() }),
+            },
+          },
+          description: 'Success response',
+        },
+        404: {
+          content: {
+            'application/json': {
+              schema: z.object({ message: z.string() }),
+            },
+          },
+          description: 'Not found response',
+        },
+        default: {
+          content: {
+            'application/json': {
+              schema: z.object({ error: z.string() }),
+            },
+          },
+          description: 'Error response',
+        },
+      },
+    })
+
+    const successHandler: RouteHandler<typeof routeWithDefault> = (c) => {
+      return c.json({ id: '123' }, 200)
+    }
+
+    const notFoundHandler: RouteHandler<typeof routeWithDefault> = (c) => {
+      return c.json({ message: 'Not Found' }, 404)
+    }
+
+    const errorHandler: RouteHandler<typeof routeWithDefault> = (c) => {
+      return c.json({ error: 'Server Error' }, 500)
+    }
+
+    const hono = new OpenAPIHono()
+    hono.openapi(routeWithDefault, successHandler)
+    hono.openapi(routeWithDefault, notFoundHandler)
+    hono.openapi(routeWithDefault, errorHandler)
+  })
 })