初始AMD和Common.js

其实就是为了多个库可以良好的合作的指定的规范

AMD---require.js Asynchronous Module Definition (AMD)
Here’s module foo with a single dependency on jquery:

//    filename: foo.js
define(['jquery'], function ($) {
    //    methods
    function myFunc(){};

    //    exposed public methods
    return myFunc;
});

第一部分是定义一个存放依赖的数组，第二部分是放当依赖可以被正常执行之后的回调函数

//    filename: foo.js
define(['jquery', 'underscore'], function ($, _) {
    //    methods
    function a(){};    //    private because it's not returned (see below)
    function b(){};    //    public because it's returned
    function c(){};    //    public because it's returned

    //    exposed public methods
    return {
        b: b,
        c: c
    }
});

多个依赖库的话，注意回调函数的参数，要对应好，如果我们将$换成$$的话，之后使用就只能使用$$的

---

Common.js---和node的写法很像

//    filename: foo.js

//    dependencies
var $ = require('jquery');

//    methods
function myFunc(){};

//    exposed public method (single)
module.exports = myFunc;

//    filename: foo.js
var $ = require('jquery');
var _ = require('underscore');

//    methods
function a(){};    //    private because it's omitted from module.exports (see below)
function b(){};    //    public because it's defined in module.exports
function c(){};    //    public because it's defined in module.exports

//    exposed public methods
module.exports = {
    b: b,
    c: c
};

---

UMD:Universal Module Definition

(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD
        define(['jquery'], factory);
    } else if (typeof exports === 'object') {
        // Node, CommonJS-like
        module.exports = factory(require('jquery'));
    } else {
        // Browser globals (root is window)
        root.returnExports = factory(root.jQuery);
    }
}(this, function ($) {
    //    methods
    function myFunc(){};

    //    exposed public method
    return myFunc;
}));

(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD
        define(['jquery', 'underscore'], factory);
    } else if (typeof exports === 'object') {
        // Node, CommonJS-like
        module.exports = factory(require('jquery'), require('underscore'));
    } else {
        // Browser globals (root is window)
        root.returnExports = factory(root.jQuery, root._);
    }
}(this, function ($, _) {
    //    methods
    function a(){};    //    private because it's not returned (see below)
    function b(){};    //    public because it's returned
    function c(){};    //    public because it's returned

    //    exposed public methods
    return {
        b: b,
        c: c
    }
}));