fix Promise is undefined issue with ie11 polyfill

Author: silesky

.changeset/khaki-spoons-laugh.md

@@ -0,0 +1,5 @@
+---
+'@segment/analytics-next': patch
+---
+
+Fix 'Promise is undefined' issue with ie11 polyfill

packages/browser/src/browser/standalone.ts

@@ -31,15 +31,14 @@ import {
 
 let ajsIdentifiedCSP = false
 
-const sendErrorMetrics = (() => {
+const sendErrorMetrics = (tags: string[]) => {
+  // this should not be instantied at the root, or it will break ie11.
   const metrics = new RemoteMetrics()
-  return (tags: string[]) => {
-    metrics.increment('analytics_js.invoke.error', [
-      ...tags,
-      `wk:${embeddedWriteKey()}`,
-    ])
-  }
-})()
+  metrics.increment('analytics_js.invoke.error', [
+    ...tags,
+    `wk:${embeddedWriteKey()}`,
+  ])
+}
 
 function onError(err?: unknown) {
   console.error('[analytics.js]', 'Failed to load Analytics.js', err)