--- sidebar_label: EventEmitter.addListener --- # EventEmitter.addListener() method > Warning: This API is now obsolete. > > please use [EventEmitter.on()](./puppeteer.eventemitter.on.md) instead. Add an event listener. #### Signature: ```typescript class EventEmitter { addListener>( type: Key, handler: Handler[Key]> ): this; } ``` ## Parameters | Parameter | Type | Description | | --------- | --------------------------------------------------------------------------------------------------------------------- | ----------- | | type | Key | | | handler | [Handler](./puppeteer.handler.md)<[EventsWithWildcard](./puppeteer.eventswithwildcard.md)<Events>\[Key\]> | | **Returns:** this