Add third parameter with response to trace and allow it to be asynchr…

…onous (#53)

README.md

@@ -408,8 +408,11 @@ await enhancedFetch("https://example.com/api/users/:role", {
 //   method: 'POST',
 //   body: '{"some":{"object":{"as":{"body":{}}}}}',
 // }
+// Response {}
 ```
 
+The `trace` function can also return a `Promise<void>` in order to send traces to an external service or database.
+
 ## typedResponse
 
 A type-safe wrapper around the `Response` object. It adds a `json` and `text` method that will parse the response with a given zod schema. If you don't provide a schema, it will return `unknown` instead of `any`, then you can also give it a generic to type cast the result.

src/api.test.ts

@@ -198,6 +198,7 @@ describe('enhancedFetch', () => {
         method: 'POST',
         body: `{"id":1,"name":{"first":"John","last":"Doe"}}`,
       },
+      expect.any(Response),
     )
   })
 
@@ -358,6 +359,7 @@ describe('makeFetcher', () => {
         body: `{"id":1,"name":{"first":"John","last":"Doe"}}`,
         headers: new Headers(),
       },
+      expect.any(Response),
     )
   })
 })

src/api.ts

@@ -67,7 +67,7 @@ function typedResponse(
  * @param requestInit the requestInit to be passed to the fetch request. It is the same as the `RequestInit` type, but it also accepts a JSON-like `body` and an object-like `query` parameter.
  * @param requestInit.body the body of the request. It will be automatically stringified so you can send a JSON-like object
  * @param requestInit.query the query parameters to be added to the URL
- * @param requestInit.trace a function that receives the URL and the requestInit and can be used to log the request
+ * @param requestInit.trace a function that receives the URL, the requestInit and a clone of the response in order to log or troubleshoot the request
  * @returns a Response with typed json and text methods
  * @example const response = await fetch("https://example.com/api/users");
  * const users = await response.json(userSchema);
@@ -83,11 +83,11 @@ async function enhancedFetch<T extends string | URL>(
   const body = ensureStringBody(reqInit.body)
   const withParams = replaceURLParams<T>(url, reqInit.params ?? ({} as never))
   const fullURL = addQueryToURL(withParams, query)
-
   const enhancedReqInit = { ...reqInit, body }
-  trace?.(fullURL, enhancedReqInit)
+
   const response = await fetch(fullURL, enhancedReqInit)
 
+  await trace?.(fullURL, enhancedReqInit, typedResponse(response.clone()))
   return typedResponse(response)
 }
 

src/types.ts

@@ -28,7 +28,11 @@ type EnhancedRequestInit<T = string> = Omit<RequestInit, 'body' | 'method'> & {
   body?: JSONValue | BodyInit | null
   query?: SearchParams
   params?: PathParams<T>
-  trace?: (...args: Parameters<typeof fetch>) => void
+  trace?: (
+    fullUrl: string | URL,
+    init: EnhancedRequestInit,
+    response: TypedResponse,
+  ) => void | Promise<void>
 }
 
 type ServiceRequestInit<T = string> = Omit<EnhancedRequestInit<T>, 'method'>