# Events

> Run your code when the unread count changes.

```ts
Iris.on("unread", (count: number) => void): void
```

## unread

The listener runs once with the current count, then on every change. Use it to show a badge on your own button when the launcher is hidden.

```js title="app.js"
const badge = document.querySelector("#help-badge");

Iris.on("unread", (count) => {
  badge.textContent = String(count);
  badge.hidden = !count;
});
```

## Console warnings

| Message | What happened | Fix |
| --- | --- | --- |
| `Iris: on ignored the listener, because the event is not "unread" or the listener is not a function.` | The event name is not `"unread"`, or the listener is not a function. | Pass `"unread"` and a function. See [Events](/reference/events/). |