[Home](./index.md) > [sip.js](./sip.js.md) > [Subscriber](./sip.js.subscriber.md) > [(constructor)](./sip.js.subscriber._constructor_.md) ## Subscriber.(constructor) Constructor. Signature: ```typescript constructor(userAgent: UserAgent, targetURI: URI, eventType: string, options?: SubscriberOptions); ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | userAgent | UserAgent | User agent. See [UserAgent](./sip.js.useragent.md) for details. | | targetURI | URI | The request URI identifying the subscribed event. | | eventType | string | The event type identifying the subscribed event. | | options | SubscriberOptions | Options bucket. See [SubscriberOptions](./sip.js.subscriberoptions.md) for details. |