---
sidebar_label: CommonEventEmitter.once
---
# CommonEventEmitter.once() method

**Signature:**

```typescript
interface CommonEventEmitter {once(event: EventType, handler: Handler): CommonEventEmitter;}
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  event | [EventType](./puppeteer.eventtype.md) |  |
|  handler | [Handler](./puppeteer.handler.md) |  |

**Returns:**

[CommonEventEmitter](./puppeteer.commoneventemitter.md)