How to unsubscribe from a socket.io subscription?

Question

Suppose there are objects making subscriptions to a socket server like so:

socket.on(\'news\', obj.socketEvent)

These objects have a short life

Answer 1

Since I had a spot of troubles making this work figured I'd chime in here as well, along with a nice updated answer for 2017. Thanks to @Pjotr for pointing out that it has to be the same callback instance.

Example with Angular2 TypeScript in a socket-io.subscriber service. Note the "newCallback" wrapper

  private subscriptions: Array<{
    key: string,
    callback: Function
  }>;

  constructor() {
    this.subscriptions = [];
  }

  subscribe(key: string, callback: Function) {
    let newCallback = (response) => callback(response);
    this.socket.on(key, newCallback);
    return this.subscriptions.push({key: key, callback: newCallback}) - 1;
  }

  unsubscribe(i: number) {
    this.socket.removeListener(this.subscriptions[i].key, this.subscriptions[i].callback);
  }