title: NodeJS + Android, Socket.io chat , app crashes on user leaving the chat room
body: <p>I am using Socket.IO for a chat app I am making. I am a beginner with both node.js and android. </p>
  
  <p>The chat actually works, but when a person leaves a chat room, any chat room, the app crashes and I have to restart it for another user/users to be able to chat again.</p>
  
  <p>The error I get is the following:</p>
  
  <blockquote>
    <p>C:\Users\Tasos\Desktop\node.js
    server\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\ultron\index.js:80
          if (this.ee._events.hasOwnProperty(event)) {
                              ^</p>
    
    <p>TypeError: this.ee._events.hasOwnProperty is not a function
        at Ultron.remove (C:\Users\Tasos\Desktop\node.js server\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\ultron\index.js:80:27)
        at Ultron.destroy (C:\Users\Tasos\Desktop\node.js server\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\ultron\index.js:116:8)
        at WebSocket.cleanupWebsocketResources (C:\Users\Tasos\Desktop\node.js
    server\node_modules\socket.io\node_modules\engine.io\node_modules\ws\lib\WebSocket.js:851:36)
        at emitNone (events.js:91:20)
        at Socket.emit (events.js:185:7)
        at endReadableNT (_stream_readable.js:974:12)
        at _combinedTickCallback (internal/process/next_tick.js:74:11)
        at process._tickCallback (internal/process/next_tick.js:98:9)</p>
  </blockquote>
  
  <p>Any hints as to what could be at fault here?</p>
  
  <p>Thanks in advance.</p>