text: class Component{
      constructor(){
          this.topics = {};
      }
      subscribe(topic,handler){
          this.topics[topic] = handler;
          controller.subscribe(topic,this);
      }
      broadcast(topic,msg){
          controller.broadcast(topic,msg);
      }
      receive(topic,msg){
          this.topics[topic].call(this,msg);
          //神来之笔 有待考察。
      }
  }
  
  module.exports = Component;
  