Nodejs中自定义事件实例

var util = require('util');
var Et = require('events').EventEmitter;
function Ticker() {
  var self = this;
  setInterval(function(){self.emit("tick")},1000);
}
util.inherits(Ticker,Et);
var ticker = new Ticker();
ticker.on("tick",function() {
  console.log("ticker");
});