RequireJS没有'我使用CDN托管库(jQuery）进行多页项目

我在一个多页项目中使用RequireJS，其Javascript文件夹结构看起来有点像这样（如何在Markdown中再次制作那些花哨的目录树？）：

common.js
lib/
-- jquery-1.9.1.min.js
-- modernizr-2.6.2.min.js
-- underscore-amd.min.js
page/
-- index.js
-- start.js
-- checkout.js

无论如何，common.js是我的主脚本文件，它是我设置配置参数的地方。这就是它的样子：

common.js文件

// Configure RequireJS
requirejs.config({
    baseUrl: "assets/js/lib",
    paths: {
        page: '../page',
        jquery: [
            '//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min',
            //If the CDN location fails, load from this location
            'jquery-1.9.1.min'
        ],
        modernizr: [
            '//cdnjs.cloudflare.com/ajax/libs/modernizr/2.6.2/modernizr.min',
            //If the CDN location fails, load from this location
            'modernizr-2.6.2.min'
        ],
        underscore: [
            'underscore-amd.min'
        ]
    }
});

所有页面调用都按预期工作（加载CDN位置），但我无法理解缩小部分。r.js优化器只是拒绝合作，即使Undercore没有指定CDN，也会抛出Error: paths fallback not supported in optimizer. Please provide a build config path override for underscore。

build.js文件

{
    appDir: '../www',
    baseUrl: 'js/lib',
    dir: '../www-built',
    mainConfigFile: '../www/assets/js/common.js',
    modules: [
        //First set up the common build layer.
        {
            //module names are relative to baseUrl
            name: '../common',
            include: ['jquery',
                      'modernizr',
                      'underscore'
            ]
        },
        // Now the page scripts
        {
            //module names are relative to baseUrl/paths config
            name: '../page-index',
            include: ['page/index'],
            exclude: ['../common']
        },
    ],
    paths: {
        jquery: "empty",
        modernizr: "empty"
    },
    optimize: "uglify2",
    removeCombined: true
}

请帮我弄清楚如何构建这个项目来创建common.js脚本以及各个页面脚本。

（注意：我的build.js文件的结构基于这个示例

更新

我已经更新了这个问题，以包含empty:的正确语法（感谢Travis！），现在构建运行时没有出现错误。然而，我的JS文件并没有被连接或放大。CSS文件在导入点，所以发生了一些事情。完成下面的build.js文件（请原谅，但她个子很高）：

{
    appDir: '../www',
    baseUrl: 'assets/js', // relative to appDir
    dir: '../www-built',
    mainConfigFile: '../www/assets/js/common.js',
    modules: [
        //First set up the common build layer.
        {
            //module names are relative to baseUrl
            name: 'common',
            //List common dependencies here. Only need to list
            //top level dependencies, "include" will find
            //nested dependencies.
            include: ['jquery',
                      'modernizr',
                      'underscore',
                      'bootstrap'
            ]
        },
        //Now set up a build layer for each page, but exclude
        //the common one. "exclude" will exclude nested
        //the nested, built dependencies from "common". Any
        //"exclude" that includes built modules should be
        //listed before the build layer that wants to exclude it.
        //"include" the appropriate "app/main*" module since by default
        //it will not get added to the build since it is loaded by a nested
        //require in the page*.js files.
        {
            //module names are relative to baseUrl/paths config
            name: 'pages/home',
            include: ['pages/home'],
            exclude: ['common']
        },
        {
            //module names are relative to baseUrl/paths config
            name: 'pages/start',
            include: ['pages/start'],
            exclude: ['common']
        },
        {
            //module names are relative to baseUrl/paths config
            name: 'pages/checkout',
            include: ['pages/checkout'],
            exclude: ['common']
        },
    ],
    paths: {
        jquery: "empty:",
        modernizr: "empty:"
//        underscore: "empty:"
    },
    optimize: "uglify2",
    optimizeCss: "standard",
    removeCombined: true,
    preserveLicenseComments: false
}

最终更新（耶！正在运行）

多亏了下面的特拉维斯，一切都很顺利！（文件正在缩小并连接）。由于他的解决方案托管在Dropbox上，将来可能会丢失（谁知道amirite？），我只总结一下他所做的修复：

1.不要将define和require调用混合在一个文件中

我有几个文件，我把它们混合在一起：

page/start.js

 define(['jquery','underscore'],function($,_) {
      ...
 });
 require(['jquery','page/start'], function($, Y) { // BAD!
      ...
 });

解决办法是这样做：

page/start.js

 require(['jquery','app/start_helper'], function($, Y) {
      ...
 });

app/start_help.js

 define(['jquery','underscore'],function($,_) {
      ...
 });

2.是"empty:"而不是"empty"

这是一个棘手的问题，尽管RequireJS文档提到了它们。

3.因为

什么样的列表只有2个要点？

真棒-现在它像一个魅力：）