# Novu React Native: TypeError: dispatchEvent parameter 1 is not of type 'Event'

## What was going on

In a fresh Expo 53 project (React Native 0.79.6) with `@novu/react-native` 3.10.1 set up per docs, every in-app step delivery throws `TypeError: Failed to execute 'dispatchEvent' on 'EventTarget': parameter 1 is not of type 'Event'` (logged three times per delivery). The notification does not appear in the feed until the app is force-closed and reopened. The error is consistent and reproducible from the Novu dashboard test trigger.

## The fix that worked

Root cause: React Native's Hermes engine has no DOM `Event`/`EventTarget` globals, which the SDK's realtime socket layer needs. Fix: install `event-target-shim` and register its globals before the SDK initializes:

```js
import { EventTarget, Event } from "event-target-shim";
globalThis.EventTarget = EventTarget;
globalThis.Event = Event;
```
Note that `event-target-polyfill` alone does not fix it (the TypeError persists); `event-target-shim` does. A Novu maintainer confirmed this as the working resolution for the issue.

## Where this came from

https://github.com/novuhq/novu/issues/9382