# Client

## Methods <a href="#on-client" id="on-client"></a>

### on(event, listener) <a href="#on-client" id="on-client"></a>

Listens for an event of the given name

```typescript
client.on(event, data => {
   console.log(data)
})
```

<table data-full-width="false"><thead><tr><th>Event</th><th>Data Type</th><th>Description</th></tr></thead><tbody><tr><td><h4><strong>app</strong></h4></td><td><a href="/pages/f29RUhLUNqUwIdvz23tc">AppetizeApp</a></td><td>The currently loaded <a href="#app-1">Appetize app</a>.</td></tr><tr><td><h4><strong>deviceInfo</strong></h4></td><td><a href="/pages/4Oh4hmuYgQZh9vQvHyUw">DeviceInfo</a></td><td>Information about the current <a href="#device">device</a>, such as type, osVersion, and screen dimensions.</td></tr><tr><td><h4><strong>error</strong></h4></td><td><code>{ message: string }</code></td><td>An error has occurred</td></tr><tr><td><h4><strong>queue</strong></h4></td><td><code>{</code> <br>  <code>type: "session | concurrent",</code> <br>  <code>position: number,</code><br>  <code>name: string</code> <br><code>}</code></td><td><p>Your position in queue for the device.</p><ul><li><strong>concurrent</strong>: You've reached the max concurrent sessions for your account and are waiting for the next available slot. The concurrent queue <strong>name</strong> will be shown.</li><li><strong>session</strong>: You're in a queue, waiting for the next available device.</li></ul></td></tr><tr><td><h4>queueEnd</h4></td><td><code>void</code></td><td>The active queue has ended.</td></tr><tr><td><h4><strong>session</strong></h4></td><td><code>Session</code></td><td>A new <a href="/pages/pykousSQWFygNgCuA8md">session</a> has started either by the client or user clicking "Tap to Play"</td></tr><tr><td><h4><strong>sessionEnded</strong></h4></td><td><code>void</code></td><td>An active session has ended.</td></tr><tr><td><h4><strong>sessionRequested</strong></h4></td><td><code>void</code></td><td>A new session has been requested either by the client or user clicking "Tap to Play"</td></tr></tbody></table>

### startSession()

Starts a session with the requested app, device, operating system, and other launch options.

```typescript
const session = await client.startSession()
```

**Parameters**

| Name      | Type                                                                  | Description                                                                                                                  |
| --------- | --------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| `config?` | [SessionConfig](/javascript-sdk/api-reference/types/sessionconfig.md) | A JSON object describing the [Configuration options](/javascript-sdk/configuration.md#configuration-options) for the device. |

### setConfig()

Update the configured app, device, operating system, or other launch options.

*Note: This will end any active sessions.*

```typescript
await client.setConfig(config)
```

**Parameters**

| Name     | Type                                                                  | Description                                                                                                                  |
| -------- | --------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| `config` | [SessionConfig](/javascript-sdk/api-reference/types/sessionconfig.md) | A JSON object describing the [Configuration options](/javascript-sdk/configuration.md#configuration-options) for the device. |

### getConfig()

Returns the current config

```javascript
const config = client.getConfig()
```

### endSession()

Ends the active session or cancels any pending session requests.

```typescript
await client.endSession()
```

## Properties

### device

The currently loaded device. See [DeviceInfo](/javascript-sdk/api-reference/types/deviceinfo.md).

### app

The currently loaded app. See [AppetizeApp](/javascript-sdk/api-reference/types/appetizeapp.md).


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.appetize.io/javascript-sdk/api-reference/client.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.