var events = require('events');

var eventEmitter = new events.EventEmitter();

var connectHandler = function connected() {
    console.log('连接成功');

    eventEmitter.emit('data-received');

};

eventEmitter.on('connection', connectHandler);

eventEmitter.on('data-received', function() {
    console.log('数据接收成功');
});

eventEmitter.emit('connection');

console.log('程序执行完毕');