WebSocketLike : Add onclose method

[FournyP]

Hi everyone,

I've tried to add a onclose listener on my websocket but the interface didn't allow me.

After verifying that underlying websocket class own a onclose method I decide to make this little PR to extends the interface.

Have a nice day.

[ricmoo]

Unfortunately this change isn’t backwards compatible.

The goal of the interface is to specify as broad a component as necessary, so that other things that can be “shaped” like a WebSocket can be used. It wasn’t meant to expose the WebSocket for other things to consume. In future versions I can add the event listener API, but this is difficult too due to the differences between WebSocket API beyond the most lowest-common-denominator.

Ideally, NodeJS will just add WebSocket to their core API. But that might still be a ways off.

For now, I recommend casting the WebSocket to whatever your WebSocket is. Usually <WebSocket> should get you to whatever your environment’s shape is although I would say it’s better practice to add the environment-specific calls to the initial object you construct, and then pass that in to the WebSocketProvider.