fetchBaseQuery: expose extraOptions to prepareHeaders

packages/toolkit/src/query/fetchBaseQuery.ts

@@ -112,7 +112,7 @@ export type FetchBaseQueryArgs = {
     api: Pick<
       BaseQueryApi,
       'getState' | 'extra' | 'endpoint' | 'type' | 'forced'
-    > & { arg: string | FetchArgs },
+    > & { arg: string | FetchArgs; extraOptions: unknown },
   ) => MaybePromise<Headers | void>
   fetchFn?: (
     input: RequestInfo,
@@ -188,6 +188,7 @@ export type FetchBaseQueryMeta = { request: Request; response?: Response }
  * @param {number} timeout
  * A number in milliseconds that represents the maximum time a request can take before timing out.
  */
+
 export function fetchBaseQuery({
   baseUrl,
   prepareHeaders = (x) => x,
@@ -212,7 +213,7 @@ export function fetchBaseQuery({
       'Warning: `fetch` is not available. Please supply a custom `fetchFn` property to use `fetchBaseQuery` on SSR environments.',
     )
   }
-  return async (arg, api) => {
+  return async (arg, api, extraOptions) => {
     const { getState, extra, endpoint, forced, type } = api
     let meta: FetchBaseQueryMeta | undefined
     let {
@@ -248,6 +249,7 @@ export function fetchBaseQuery({
         endpoint,
         forced,
         type,
+        extraOptions,
       })) || headers
 
     // Only set the content-type to json if appropriate. Will not be true for FormData, ArrayBuffer, Blob, etc.

packages/toolkit/src/query/tests/fetchBaseQuery.test.tsx

@@ -2,6 +2,7 @@ import { createSlice } from '@reduxjs/toolkit'
 import { createApi, fetchBaseQuery } from '@reduxjs/toolkit/query'
 import { headersToObject } from 'headers-polyfill'
 import { HttpResponse, delay, http } from 'msw'
+// @ts-ignore
 import nodeFetch from 'node-fetch'
 import queryString from 'query-string'
 import { vi } from 'vitest'
@@ -852,6 +853,51 @@ describe('fetchBaseQuery', () => {
       expect(_forced).toBe(true)
       expect(_extra).toBe(fakeAuth0Client)
     })
+
+    test('can be instantiated with a `ExtraOptions` generic and `extraOptions` will be available in `prepareHeaders', async () => {
+      const prepare = vitest.fn()
+      const baseQuery = fetchBaseQuery({
+        prepareHeaders(headers, api) {
+          expectTypeOf(api.extraOptions).toEqualTypeOf<unknown>()
+          prepare.apply(undefined, arguments as unknown as any[])
+        },
+      })
+      baseQuery('http://example.com', commonBaseQueryApi, {
+        foo: 'baz',
+        bar: 5,
+      })
+      expect(prepare).toHaveBeenCalledWith(
+        expect.anything(),
+        expect.objectContaining({ extraOptions: { foo: 'baz', bar: 5 } }),
+      )
+
+      // ensure types
+      createApi({
+        baseQuery,
+        endpoints(build) {
+          return {
+            testQuery: build.query({
+              query: () => ({ url: '/echo', headers: {} }),
+              extraOptions: {
+                foo: 'asd',
+                bar: 1,
+              },
+            }),
+            testMutation: build.mutation({
+              query: () => ({
+                url: '/echo',
+                method: 'POST',
+                credentials: 'omit',
+              }),
+              extraOptions: {
+                foo: 'qwe',
+                bar: 15,
+              },
+            }),
+          }
+        },
+      })
+    })
   })
 
   test('can pass `headers` into `fetchBaseQuery`', async () => {