# RegisteredWatcher

Registered watcher objects are plain objects with a few convenience methods and properties. These objects can only be obtained via the [`.watchers.add`](https://api.lampix.co/application-development/lampixjs/api/watchers.add) method (for the time being), and **all watcher management is done through the interface they provide**. If watcher management (e.g pausing, resuming, removing, updating) is required by an application, they should be saved in the app's state.

## Properties

* `source` (*Object*): A replica of the object provided to `.watchers.add`.
* `state` (*Object*): An object representing the current state of the registered watcher.
  * `active` (*boolean*): Represents whether computer vision processes are active for the watcher in question. Changed by `pause` and `resume` methods.
* `onClassification` (*Function*): Configurable handler for the classification event. See [Watcher](https://api.lampix.co/application-development/lampixjs/api/watcher) for details.
* `onLocation` (*Function*, Optional): Configurable handler for the location event. See [Watcher](https://api.lampix.co/application-development/lampixjs/api/watcher) for details.
* `channel` (*Object*): Channel to use to send data to the watcher past the point of initialization

## Methods

Note that all of these methods return a promise with no resolve value.

### [`pause()`](#pause) <a href="#pause" id="pause"></a>

Pauses computer vision activity (classification, location) for the registered watcher.

### [`resume()`](#resume) <a href="#resume" id="resume"></a>

Resumes computer vision activity (classification, location) for the registered watcher.

### [`remove()`](#remove) <a href="#remove" id="remove"></a>

Removes the registered watcher.

### [`channel.send(data)`](#watcher-channel) <a href="#watcher-channel" id="watcher-channel"></a>

Sends data to be acted upon by all listeners registered in the watcher. Mainly for use with custom watchers. Can be anything valid according to the [`JSON.stringify`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify) method

#### Notes

Adding and removing watchers can have an impact on performance. If you intend to reuse the same watcher, consider using the [`pause`](#pause) and [`resume`](#resume) methods instead.

### [`updateShape(shape)`](#updateShape) <a href="#updateshape" id="updateshape"></a>

Replaces the shape of a registered watcher with the new one provided.