WebSocket onError handler incorrectly accepts a CloseEvent

[ShukantPal]

I found a log in our application from Colyseus.js:

Room, onError (undefined): undefined

That's coming from here:

colyseus.js/src/Room.ts

Line 76 in 2feff0a

console.warn(`Room, onError (${e.code}): ${e.reason}`);

The onerror event handler is incorrectly assuming that the WebSocket will pass a CloseEvent. A plain Event is passed instead. See the WebSocket API's error event has no specific type, while the WebSocket API's close event does.