Merge pull request #4638 from kyletsang/prepareheaders-args

Pass query args to prepareHeaders function

docs/rtk-query/api/fetchBaseQuery.mdx

@@ -64,7 +64,7 @@ type FetchBaseQueryArgs = {
     api: Pick<
       BaseQueryApi,
       'getState' | 'extra' | 'endpoint' | 'type' | 'forced'
-    >,
+    > & { arg: string | FetchArgs },
   ) => MaybePromise<Headers | void>
   fetchFn?: (
     input: RequestInfo,
@@ -105,7 +105,7 @@ Typically a string like `https://api.your-really-great-app.com/v1/`. If you don'
 
 _(optional)_
 
-Allows you to inject headers on every request. You can specify headers at the endpoint level, but you'll typically want to set common headers like `authorization` here. As a convenience mechanism, the second argument allows you to use `getState` to access your redux store in the event you store information you'll need there such as an auth token. Additionally, it provides access to `extra`, `endpoint`, `type`, and `forced` to unlock more granular conditional behaviors.
+Allows you to inject headers on every request. You can specify headers at the endpoint level, but you'll typically want to set common headers like `authorization` here. As a convenience mechanism, the second argument allows you to use `getState` to access your redux store in the event you store information you'll need there such as an auth token. Additionally, it provides access to `arg`, `extra`, `endpoint`, `type`, and `forced` to unlock more granular conditional behaviors.
 
 You can mutate the `headers` argument directly, and returning it is optional.
 
@@ -114,6 +114,7 @@ type prepareHeaders = (
   headers: Headers,
   api: {
     getState: () => unknown
+    arg: string | FetchArgs
     extra: unknown
     endpoint: string
     type: 'query' | 'mutation'
@@ -303,8 +304,8 @@ The default response handler is `"json"`, which is equivalent to the following f
 
 ```ts title="Default responseHandler"
 const defaultResponseHandler = async (res: Response) => {
-  const text = await res.text();
-  return text.length ? JSON.parse(text) : null;
+  const text = await res.text()
+  return text.length ? JSON.parse(text) : null
 }
 ```
 

packages/toolkit/src/query/fetchBaseQuery.ts

@@ -112,7 +112,7 @@ export type FetchBaseQueryArgs = {
     api: Pick<
       BaseQueryApi,
       'getState' | 'extra' | 'endpoint' | 'type' | 'forced'
-    >,
+    > & { arg: string | FetchArgs },
   ) => MaybePromise<Headers | void>
   fetchFn?: (
     input: RequestInfo,
@@ -164,9 +164,9 @@ export type FetchBaseQueryMeta = { request: Request; response?: Response }
  * The base URL for an API service.
  * Typically in the format of https://example.com/
  *
- * @param {(headers: Headers, api: { getState: () => unknown; extra: unknown; endpoint: string; type: 'query' | 'mutation'; forced: boolean; }) => Headers} prepareHeaders
+ * @param {(headers: Headers, api: { getState: () => unknown; arg: string | FetchArgs; extra: unknown; endpoint: string; type: 'query' | 'mutation'; forced: boolean; }) => Headers} prepareHeaders
  * An optional function that can be used to inject headers on requests.
- * Provides a Headers object, as well as most of the `BaseQueryApi` (`dispatch` is not available).
+ * Provides a Headers object, most of the `BaseQueryApi` (`dispatch` is not available), and the arg passed into the query function.
  * Useful for setting authentication or headers that need to be set conditionally.
  *
  * @link https://developer.mozilla.org/en-US/docs/Web/API/Headers
@@ -225,7 +225,8 @@ export function fetchBaseQuery({
       ...rest
     } = typeof arg == 'string' ? { url: arg } : arg
 
-    let abortController: AbortController | undefined, signal = api.signal
+    let abortController: AbortController | undefined,
+      signal = api.signal
     if (timeout) {
       abortController = new AbortController()
       api.signal.addEventListener('abort', abortController.abort)
@@ -242,6 +243,7 @@ export function fetchBaseQuery({
     config.headers =
       (await prepareHeaders(headers, {
         getState,
+        arg,
         extra,
         endpoint,
         forced,
@@ -297,7 +299,10 @@ export function fetchBaseQuery({
       }
     } finally {
       if (timeoutId) clearTimeout(timeoutId)
-      abortController?.signal.removeEventListener('abort', abortController.abort)
+      abortController?.signal.removeEventListener(
+        'abort',
+        abortController.abort,
+      )
     }
     const responseClone = response.clone()
 

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

@@ -799,16 +799,17 @@ describe('fetchBaseQuery', () => {
     })
 
     test('prepareHeaders provides extra api information for getState, extra, endpoint, type and forced', async () => {
-      let _getState, _extra, _endpoint, _type, _forced
+      let _getState, _arg: any, _extra, _endpoint, _type, _forced
 
       const baseQuery = fetchBaseQuery({
         baseUrl,
         fetchFn: fetchFn as any,
         prepareHeaders: (
           headers,
-          { getState, extra, endpoint, type, forced },
+          { getState, arg, extra, endpoint, type, forced },
         ) => {
           _getState = getState
+          _arg = arg
           _endpoint = endpoint
           _type = type
           _forced = forced
@@ -845,6 +846,7 @@ describe('fetchBaseQuery', () => {
       await doRequest()
 
       expect(_getState).toBeDefined()
+      expect(_arg!.url).toBe('/echo')
       expect(_endpoint).toBe('someEndpointName')
       expect(_type).toBe('query')
       expect(_forced).toBe(true)