feat(openapi-fetch): add global querySerializer option (#1182)

.changeset/four-carpets-push.md

@@ -0,0 +1,5 @@
+---
+"openapi-fetch": minor
+---
+
+Add global `querySerializer()` option to `createClient()`

packages/openapi-fetch/README.md

@@ -188,6 +188,35 @@ Note that this happens **at the request level** so that you still get correct ty
 
 _Thanks, [@ezpuzz](https://github.com/ezpuzz)!_
 
+Provide a `querySerializer()` to `createClient()` to globally override the default `URLSearchParams` serializer. Serializers provided to a specific request method still override the global default.
+
+```ts
+import createClient, { defaultSerializer } from "openapi-fetch";
+import { paths } from "./v1"; // generated from openapi-typescript
+import { queryString } from "query-string";
+
+const { get, post } = createClient<paths>({
+  baseUrl: "https://myapi.dev/v1/",
+  querySerializer: (q) => queryString.stringify(q, { arrayFormat: "none" }), // Override the default `URLSearchParams` serializer
+});
+
+const { data, error } = await get("/posts/", {
+  params: {
+    query: { categories: ["dogs", "cats", "lizards"] }, // Use the serializer specified in `createClient()`
+  },
+});
+
+const { data, error } = await get("/images/{image_id}", {
+  params: {
+    path: { image_id: "image-id" },
+    query: { size: 512 },
+  },
+  querySerializer: defaultSerializer, // Use `openapi-fetch`'s `URLSearchParams` serializer
+});
+```
+
+_Thanks, [@psychedelicious](https://github.com/psychedelicious)!_
+
 ## Examples
 
 ### 🔒 Handling Auth

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

@@ -387,6 +387,37 @@ describe("client", () => {
 
         expect(fetchMocker.mock.calls[0][0]).toBe("/blogposts/my-post?alpha=2&beta=json");
       });
+
+      it("applies global serializer", async () => {
+        const client = createClient<paths>({
+          querySerializer: (q) => `alpha=${q.version}&beta=${q.format}`,
+        });
+        mockFetchOnce({ status: 200, body: "{}" });
+        await client.get("/blogposts/{post_id}", {
+          params: {
+            path: { post_id: "my-post" },
+            query: { version: 2, format: "json" },
+          },
+        });
+
+        expect(fetchMocker.mock.calls[0][0]).toBe("/blogposts/my-post?alpha=2&beta=json");
+      });
+
+      it("overrides global serializer if provided", async () => {
+        const client = createClient<paths>({
+          querySerializer: () => "query",
+        });
+        mockFetchOnce({ status: 200, body: "{}" });
+        await client.get("/blogposts/{post_id}", {
+          params: {
+            path: { post_id: "my-post" },
+            query: { version: 2, format: "json" },
+          },
+          querySerializer: (q) => `alpha=${q.version}&beta=${q.format}`,
+        });
+
+        expect(fetchMocker.mock.calls[0][0]).toBe("/blogposts/my-post?alpha=2&beta=json");
+      });
     });
   });
 

packages/openapi-fetch/src/index.ts

@@ -10,6 +10,8 @@ interface ClientOptions extends RequestInit {
   baseUrl?: string;
   /** custom fetch (defaults to globalThis.fetch) */
   fetch?: typeof fetch;
+  /** global querySerializer */
+  querySerializer?: QuerySerializer<unknown>;
 }
 export interface BaseParams {
   params?: { query?: Record<string, unknown> };
@@ -82,15 +84,15 @@ export function createFinalURL<O>(url: string, options: { baseUrl?: string; para
 }
 
 export default function createClient<Paths extends {}>(clientOptions: ClientOptions = {}) {
-  const { fetch = globalThis.fetch, ...options } = clientOptions;
+  const { fetch = globalThis.fetch, querySerializer: globalQuerySerializer, ...options } = clientOptions;
 
   const defaultHeaders = new Headers({
     ...DEFAULT_HEADERS,
     ...(options.headers ?? {}),
   });
 
   async function coreFetch<P extends keyof Paths, M extends HttpMethod>(url: P, fetchOptions: FetchOptions<M extends keyof Paths[P] ? Paths[P][M] : never>): Promise<FetchResponse<M extends keyof Paths[P] ? Paths[P][M] : unknown>> {
-    const { headers, body: requestBody, params = {}, parseAs = "json", querySerializer = defaultSerializer, ...init } = fetchOptions || {};
+    const { headers, body: requestBody, params = {}, parseAs = "json", querySerializer = globalQuerySerializer ?? defaultSerializer, ...init } = fetchOptions || {};
 
     // URL
     const finalURL = createFinalURL(url as string, { baseUrl: options.baseUrl, params, querySerializer });