# Module: ol/Observable

This documentation is for OpenLayers v10.9.0. The latest is v.

## ol/Observable

### Classes

Observable

### Functions

#### unByKey(key)

Observable.js, line 181

      import {unByKey} from 'ol/Observable';

  Removes an event listener using the key returned by `on()` or `once()`.

  Name | Type | Description
  --- | --- | ---
  `key` | The key returned by `on()` or `once()` (or an array of keys).
  Name | Type | Description
  --- | --- | ---
  `listener` | ListenerFunction | Listener.
  `target` | EventTargetLike | Target.
  `type` | string | Type.

### Type Definitions

#### EventTypes{'change'} {'error'}