events模块->EventEmitter

var EventEmitter = require('events');

var util = require('util');

var MyEmitter = function() {
    
}

util.inherits(MyEmitter, EventEmitter);

const myEmitter = new MyEmitter();


myEmitter.on('event', function(a, b) {
    console.log(a, b, this);
});

myEmitter.emit('event', 'a', 'b');

// a b { _events: { event: [Function] } }