***

id: f5023d60-525a-48d4-b04f-2f03a79464f8
title: once
slug: /node/reference/video/client/once
description: once method for the Video Client class.
max-toc-depth: 3
----------------

### once

* **once**(`event`, `fn`)

Attaches an event handler to the specified event. The handler will fire only once.

#### Parameters

| Name    | Type     | Description                                                                                                               |
| :------ | :------- | :------------------------------------------------------------------------------------------------------------------------ |
| `event` | `string` | Name of the event. See [Events](/docs/server-sdk/v3/node/reference/video/client/events) for the list of available events. |
| `fn`    | Function | An event handler.                                                                                                         |