Zendesk Chat Widget: Open minimized chat window on new message

showOnUnread.js

/* 
Show the chat window if the number of unread messages > 0 and the chat window is not currently displayed.
  see references:
    setOnUnreadMsgs - https://api.zopim.com/files/meshim/widget/controllers/LiveChatAPI-js.html#setOnUnreadMsgs
    getDisplay - https://api.zopim.com/files/meshim/widget/controllers/liveChatAPI/Window-js.html#$zopim.livechat.window.getDisplay
    show - https://api.zopim.com/files/meshim/widget/controllers/liveChatAPI/Window-js.html#$zopim.livechat.window.show
*/ 
$zopim(function() {
  $zopim.livechat.setOnUnreadMsgs(function(numUnread){
    if(numUnread > 0 && !$zopim.livechat.window.getDisplay()) {
      $zopim.livechat.window.show();
    }
  });
});