feat(browser): support fetchParameters (#2567)

Co-authored-by: Phillip Kuang <>

Author: kuangp

packages/browser/src/transports/fetch.ts

@@ -35,6 +35,10 @@ export class FetchTransport extends BaseTransport {
       referrerPolicy: (supportsReferrerPolicy() ? 'origin' : '') as ReferrerPolicy,
     };
 
+    if (this.options.fetchParameters !== undefined) {
+      Object.assign(options, this.options.fetchParameters);
+    }
+
     if (this.options.headers !== undefined) {
       options.headers = this.options.headers;
     }

packages/browser/test/unit/transports/fetch.test.ts

@@ -156,5 +156,29 @@ describe('FetchTransport', () => {
         }),
       ).equal(true);
     });
+
+    it('passes in fetch parameters', async () => {
+      transport = new Transports.FetchTransport({
+        dsn: testDsn,
+        fetchParameters: {
+          credentials: 'include',
+        },
+      });
+      const response = { status: 200 };
+
+      fetch.returns(Promise.resolve(response));
+
+      const res = await transport.sendEvent(payload);
+
+      expect(res.status).equal(Status.Success);
+      expect(
+        fetch.calledWith(transportUrl, {
+          body: JSON.stringify(payload),
+          credentials: 'include',
+          method: 'POST',
+          referrerPolicy: 'origin',
+        }),
+      ).equal(true);
+    });
   });
 });

packages/types/src/transport.ts

@@ -34,4 +34,6 @@ export interface TransportOptions {
   httpsProxy?: string;
   /** HTTPS proxy certificates path */
   caCerts?: string;
+  /** Fetch API init parameters */
+  fetchParameters?: { [key: string]: string };
 }