Add support for Node.js built-in WebSocket?

[thernstig]

Is your feature request related to a problem? Please describe.
I would like to decrease number of dependencies as it is a maintenance burden.

Describe the solution you'd like
Node.js 21 includes native WebSocket support under the --experimental-websocket. It would be nice if there was some kind of opt-in behavior to use it.

Describe alternatives you've considered
Keep using the ws socket.io dependency.

Additional context
I am not sure if this is even feasible. You'd need to install the ws package anyway for those running on Node <21. So it is possible this issue shall be closed immediately with "no action".

[darrachequesne]

Thanks for the heads-up! We could indeed use the new WebSocket client, though I'm not sure how we could conditionally import it and support both Node.js < 21 and Node.js > 21.

Source: https://github.com/socketio/engine.io-client/blob/main/lib/transports/websocket-constructor.ts

[thernstig]

@darrachequesne maybe a bigger problem is if you support other platforms (Deno?) then it might be even more problematic?

Publishing different npm packages in your build pipeline would be one way, but maybe that is not wanted.