feat(browser): Flush offline queue on flush and browser online event

packages/browser/src/transports/offline.ts

@@ -1,5 +1,6 @@
 import type { BaseTransportOptions, Envelope, OfflineStore, OfflineTransportOptions, Transport } from '@sentry/core';
 import { makeOfflineTransport, parseEnvelope, serializeEnvelope } from '@sentry/core';
+import { WINDOW } from '../helpers';
 import { makeFetchTransport } from './fetch';
 
 // 'Store', 'promisifyRequest' and 'createStore' were originally copied from the 'idb-keyval' package before being
@@ -158,7 +159,15 @@
 function makeIndexedDbOfflineTransport<T>(
   createTransport: (options: T) => Transport,
 ): (options: T & BrowserOfflineTransportOptions) => Transport {
-  return options => createTransport({ ...options, createStore: createIndexedDbStore });
+  return options => {
+    const transport = createTransport({ ...options, createStore: createIndexedDbStore });
+
+    WINDOW.addEventListener('online', async _ => {
+      await transport.flush();
+    });
+
+    return transport;
+  };
 }
 
 /**

packages/core/src/transports/offline.ts

@@ -170,7 +170,15 @@ export function makeOfflineTransport<TO>(
 
     return {
       send,
-      flush: t => transport.flush(t),
+      flush: timeout => {
+        // If there's no timeout, we should attempt to flush the offline queue.
+        if (timeout === undefined) {
+          retryDelay = START_DELAY;
+          flushIn(MIN_DELAY);
+        }
+
+        return transport.flush(timeout);
+      },
     };
   };
 }