fix(openapi-fetch): treat default response as error

Author: drwpow

.changeset/sixty-bobcats-jam.md

@@ -0,0 +1,5 @@
+---
+"openapi-fetch": patch
+---
+
+Treat `default` response as error

docs/src/content/docs/openapi-fetch/index.md

@@ -134,4 +134,5 @@ All methods return an object with **data**, **error**, and **response**.
 
 - **data** will contain that endpoint’s `2xx` response if the server returned `2xx`; otherwise it will be `undefined`
 - **error** likewise contains that endpoint’s `4xx`/`5xx` response if the server returned either; otherwise it will be `undefined`
+  - _Note: `default` will also be interpreted as `error`, since its intent is handling unexpected HTTP codes_
 - **response** has response info like `status`, `headers`, etc. It is not typechecked.

packages/openapi-fetch/README.md

@@ -129,6 +129,7 @@ All methods return an object with **data**, **error**, and **response**.
 
 - **data** will contain that endpoint’s `2xx` response if the server returned `2xx`; otherwise it will be `undefined`
 - **error** likewise contains that endpoint’s `4xx`/`5xx` response if the server returned either; otherwise it will be `undefined`
+  - _Note: `default` will also be interpreted as `error`, since its intent is handling unexpected HTTP codes_
 - **response** has response info like `status`, `headers`, etc. It is not typechecked.
 
 ## API

packages/openapi-fetch/src/index.test.ts

@@ -194,6 +194,18 @@ describe("client", () => {
     });
     expect((await client.get("/self", {})).data).toBe(data);
   });
+
+  it("treats `default` as an error", async () => {
+    const client = createClient<paths>({ headers: { "Cache-Control": "max-age=10000000" } });
+    fetchMocker.mockResponseOnce(() => ({ status: 500, headers: { "Content-Type": "application/json" }, body: JSON.stringify({ code: 500, message: "An unexpected error occurred" }) }));
+    const { error } = await client.get("/default-as-error", {});
+
+    // discard `data` object
+    if (!error) throw new Error("treats `default` as an error: error response should be present");
+
+    // assert `error.message` doesn’t throw TS error
+    expect(error.message).toBe("An unexpected error occurred");
+  });
 });
 
 describe("get()", () => {

packages/openapi-fetch/src/index.ts

@@ -45,7 +45,7 @@ export type RequestBody<O> = undefined extends RequestBodyJSON<O> ? { body?: Req
 export type QuerySerializer<O> = (query: O extends { parameters: { query: any } } ? O["parameters"]["query"] : Record<string, unknown>) => string;
 export type RequestOptions<T> = Params<T> & RequestBody<T> & { querySerializer?: QuerySerializer<T> };
 export type Success<O> = FilterKeys<FilterKeys<O, OkStatus>, "content">;
-export type Error<O> = FilterKeys<FilterKeys<O, ErrorStatus>, "content">;
+export type Error<O> = FilterKeys<FilterKeys<O, ErrorStatus | "default">, "content">;
 
 // fetch types
 export type FetchOptions<T> = RequestOptions<T> & Omit<RequestInit, "body">;

packages/openapi-fetch/test/v1.d.ts

@@ -141,6 +141,13 @@ export interface paths {
       };
     };
   };
+  "/default-as-error": {
+    get: {
+      responses: {
+        default: components["responses"]["Error"];
+      };
+    };
+  };
   "/anyMethod": {
     get: {
       responses: {

packages/openapi-fetch/test/v1.yaml

@@ -124,6 +124,11 @@ paths:
           $ref: '#/components/responses/CreateTag'
         500:
           $ref: '#/components/responses/Error'
+  /default-as-error:
+    get:
+      responses:
+        default:
+          $ref: '#/components/responses/Error'
   /anyMethod:
     get:
       responses: