Bind sendBeacon to navigator

packages/next/client/performance-relayer.ts

@@ -47,13 +47,26 @@ function onReport(metric: Metric): void {
       type: 'application/x-www-form-urlencoded',
     })
     const vitalsUrl = 'https://vitals.vercel-insights.com/v1/vitals'
-    ;(navigator.sendBeacon && navigator.sendBeacon(vitalsUrl, blob)) ||
+    // Navigator has to be bound to ensure it does not error in some browsers
+    // https://xgwang.me/posts/you-may-not-know-beacon/#it-may-throw-error%2C-be-sure-to-catch
+    const send = navigator.sendBeacon && navigator.sendBeacon.bind(navigator)
+
+    function fallbackSend() {
       fetch(vitalsUrl, {
         body: blob,
         method: 'POST',
         credentials: 'omit',
         keepalive: true,
-      })
+        // console.error is used here as when the fetch fails it does not affect functioning of the app
+      }).catch(console.error)
+    }
+
+    try {
+      // If send is undefined it'll throw as well. This reduces output code size.
+      send!(vitalsUrl, blob)
+    } catch (err) {
+      fallbackSend()
+    }
   }
 }