This is a pretty common pattern in the Node.js ecosystem, for example, the Server object of the core http module defines methods such as listen(), close(), setTimeout(), and internally it also inherits from the EventEmitter function, thus allowing it to produce events, such as request, when a new request is received, or connection, when a new connection is established, or closed, when the server is closed. Other notable examples of objects extending the EventEmitter are Node.js streams.
