Added WebSocket types

[benycodes]

Added the following:

interface WebSocket {
  accept(): void;
}

declare class WebSocketPair {
  0: WebSocket;
  1: WebSocket;
}

interface ResponseInit {
  webSocket?: WebSocket;
}

Closes:
#84

[benycodes]

@koeninger

[vicary]

@benycodes Should ResponseInit be Response?

[RamIdeas]

@benycodes Should ResponseInit be Response?

No. ResponseInit is the 2nd param to the Response constructor and you pass the 'client' websocket from the WebSocketPair as the webSocket property of ResponseInit

[ItsWendell]

@benycodes Thanks for doing this, in response to @vicary and @RamIdeas, the Response object should also be able to return a webSocket.

For example, if you have a connection from your worker to a durable object through WebSockets (or another WebSocket server), the fetch request to upgrade that connection to WebSockets will return the webSocket property in the Response.

So yes, we should have webSocket in Response too.

[vicary]

@ItsWendell thanks for the clarification. Yes, it makes sense to include webSocket in both Response and ResponseInit.

[lukeed]

Sorry, I see that there's been back and forth on this, but this actually isn't correct. Extending an Array means that this could be possible, which it isn't:

let [client, server] = new WebSocketPair;

The correct solution is to do the equivalent of what worktop does, which is this:

Suggested change

	declare class WebSocketPair extends Array {
	0: WebSocket;
	1: WebSocket;
	}
	declare const WebSocketPair: {
	new(): {
	0: WebSocket;
	1: WebSocket;
	};
	};

Here's a Playground to see the differences.

[mrkldshv]

I see this hasn't been touched for some time. Would that be okay if I take over this PR or create a new one?

[lukeed]

No reason for another PR here, thank you though. There's some other work being done wrt types right now, hence the temporary pause.

[mrbbot]

#112 has now been merged, which includes the new WebSocket and WebSocketPair types.