Merge pull request #3052 from RoelVB/fix/optional-headers-in-batch

fixing content-type header bug in 204 response parsing

packages/graph/batching.ts

@@ -374,7 +374,6 @@ function parseResponse(graphResponse: IGraphBatchResponse): ParsedGraphResponse
         // we create the request id by adding 1 to the index, so we place the response by subtracting one to match
         // the array of requests and make it easier to map them by index
         const responseId = parseInt(response.id, 10) - 1;
-        const contentType = response.headers["Content-Type"];
         const { status, statusText, headers, body } = response;
         const init = { status, statusText, headers };
 
@@ -395,7 +394,7 @@ function parseResponse(graphResponse: IGraphBatchResponse): ParsedGraphResponse
             // eslint-disable-next-line @typescript-eslint/dot-notation
             parsedResponses[responseId] = new Response(jsS({ location: headers["Location"] || "" }), init);
 
-        } else if (status === 200 && /^image[\\|/]/i.test(contentType)) {
+        } else if (status === 200 && /^image[\\|/]/i.test(headers["Content-Type"] || "")) {
 
             // this handles the case where image content is returned as base 64 data in the batch body, such as /me/photos/$value (https://github.com/pnp/pnpjs/issues/2825)