# grove.off()

## Signature

```ts
grove.off(type: string, callback: Function): void
```

## Availability

All packaged runtimes. No capability required.

## Parameters

| Parameter | Required | Description |
| --- | --- | --- |
| `type` | Yes | The exact event name passed to on. |
| `callback` | Yes | The same function object passed to on. An equivalent new arrow function does not match. |

## Return value

Returns `undefined`.

## Behavior and errors

Removes the first matching subscription. Missing event names or callbacks are a no-op. It does not clear the retained event payload or cancel a callback already running. Delivery iterates a snapshot of listeners, so removal does not alter that in-progress iteration.

## Example

```js
function onLifecycle(event) {
  console.debug('Lifecycle:', event.state)
}
grove.on('lifecycle', onLifecycle)
grove.off('lifecycle', onLifecycle)
```

See [grove.on()](grove-on.md).