title: Socket Io client creates multiple listener on Vue Componet
body: <p>I am Using Vue.js as the front-end framework. </p>
  
  <p>I am adding the socket.io listener on a component using created life-cycle hook.</p>
  
  <pre><code>created () {
      // socket listener
      this.$socket.on('event', (response) =&gt; { .... })
  }
  </code></pre>
  
  <p>Now if the component is unmounted and later remounted then two listener are created.</p>
  
  <p>I tried using "once" in place of "on" but same problem.</p>
  
  <p>How Can I make sure that only one Listener is active?</p>
  
  <p>Note: The socket component is added to Vue as Instance Property.</p>