fix(web-vitals): Add error handling for invalid object keys in WeakMap (#18809)

A customer experienced the following issue on iOS Safari 18.6.2:
`TypeError: WeakMap keys must be objects or non-registered symbols`.

The culprit is probably in web vitals `initUnique` function (which is
vendored in).

This fix adds a try/catch to handle edge cases where invalid keys are
passed to WeakMap, returning a new instance without caching when
validation fails.



Closes #18810 (added automatically)

Co-authored-by: Nicolas Hrubec <[email protected]>

Author: s1gr1d

packages/browser-utils/src/metrics/web-vitals/lib/initUnique.ts

@@ -22,8 +22,16 @@ const instanceMap: WeakMap<object, unknown> = new WeakMap();
  * identity object was previously used.
  */
 export function initUnique<T>(identityObj: object, ClassObj: new () => T): T {
-  if (!instanceMap.get(identityObj)) {
-    instanceMap.set(identityObj, new ClassObj());
+  try {
+    if (!instanceMap.get(identityObj)) {
+      instanceMap.set(identityObj, new ClassObj());
+    }
+    return instanceMap.get(identityObj)! as T;
+  } catch (e) {
+    // --- START Sentry-custom code (try/catch wrapping) ---
+    // Fix for cases where identityObj is not a valid key for WeakMap (sometimes a problem in Safari)
+    // Just return a new instance without caching it in instanceMap
+    return new ClassObj();
   }
-  return instanceMap.get(identityObj)! as T;
+  // --- END Sentry-custom code ---
 }