guard against self.socket being null

Author: feross

lib/client/websocket-tracker.js

@@ -95,10 +95,12 @@ WebSocketTracker.prototype.destroy = function (cb) {
   clearInterval(self.interval)
   clearTimeout(self.reconnectTimer)
 
-  self.socket.removeListener('connect', self._onSocketConnectBound)
-  self.socket.removeListener('data', self._onSocketDataBound)
-  self.socket.removeListener('close', self._onSocketCloseBound)
-  self.socket.removeListener('error', self._onSocketErrorBound)
+  if (self.socket) {
+    self.socket.removeListener('connect', self._onSocketConnectBound)
+    self.socket.removeListener('data', self._onSocketDataBound)
+    self.socket.removeListener('close', self._onSocketCloseBound)
+    self.socket.removeListener('error', self._onSocketErrorBound)
+  }
 
   self._onSocketConnectBound = null
   self._onSocketErrorBound = null
@@ -120,9 +122,8 @@ WebSocketTracker.prototype.destroy = function (cb) {
   if (socketPool[self.announceUrl].consumers === 0) {
     delete socketPool[self.announceUrl]
 
-    self.socket.on('error', noop) // ignore all future errors
-
     try {
+      self.socket.on('error', noop) // ignore all future errors
       self.socket.destroy(cb)
     } catch (err) {
       cb(null)