Node.JS - 簡化函式宣告

目前在學習Node.JS
有一些地方看不太懂，
多看一些網站，總算是了解了，
原來是省略了一些部分，
不過，這樣的寫法可讀性應該會變差，
但是，還是必需要了解別人是在寫什麼。


原本的程式碼

// get the reference of EventEmitter class of events module
var events = require('events');
// create an object of EventEmitter class by using above reference.
var em = new events.EventEmitter();

// bind the function with a event
em.on('FirstEvent', function (data) {
 console.log('First subscriber:' + data);
});
// emit event
em.emit('FirstEvent', 'I have entered the first Event!!');

實際上可以寫的清楚一點如下，
可讀性比較高

// get the reference of EventEmitter class of events module
var events = require('events');
//create an object of EventEmitter class by using above reference.
var em = new events.EventEmitter();

// Create an event handler:
var myEventHandler = function (data) {
 console.log('First subscriber:' + data);
}
// bind the function with a event
em.on('FirstEvent', myEventHandler);

//bind the function with a event
//em.on('FirstEvent', function (data) {
// console.log('First subscriber:' + data);
//});
//emit event
em.emit('FirstEvent', 'I have entered the first Event!!');

這個寫法必需懂，
因為看起來很多Node.JS都會用這個寫法！！

參考資料：
Node.js Events
Day11 - Node.js EventEmitter