A RequireJS compatible plugin to provide shimming capabilities declaratively.

use.js

/* RequireJS Use Plugin v0.1.0
 * Copyright 2012, Tim Branyen (@tbranyen)
 * use.js may be freely distributed under the MIT license.
*/
define(function() {
  var buildMap = {};

  return {
    version: "0.1.0",

    // Invoked by the AMD builder, passed the path to resolve, the require
    // function, done callback, and the configuration options.
    //
    // Configuration format
    // --------------------------------------------------------------------------
    //
    // The string property used in attach will resolve to window[stringProp]
    // Functions are evaluated in the scope of the window and passed all
    // arguments.
    //
    // require.config({
    //   use: {
    //     "libs/underscore": {
    //       attach: "_"
    //     },
    //  
    //     "libs/backbone": {
    //       deps: ["use!underscore", "jquery"],
    //       attach: function(_, $) {
    //         return this.Backbone.noConflict();
    //       }
    //     }
    //   }
    // });
    //
    load: function(name, req, load, config) {
      var module = config.use && config.use[name];

      // No module to load so return early.
      if (!module) {
        return load();
      }

      if(config.isBuild) {
        var fs = require.nodeRequire("fs");
        var url = req.toUrl(name);

        if(/\.js$/.test(url) === false) {
          url += ".js";
        }

        buildMap[name] = {
          content: fs.readFileSync(url, "utf8"),
          attach: module.attach
        };

        return load();
      }

      // Read the current module configuration for any dependencies that are
      // required to run this particular non-AMD module.
      req(module.deps || [], function() {
        // Require this module
        req([name], function() {
          // Attach property
          var attach = config.use[name].attach;

          // Return the correct attached object
          if (typeof attach == "function") {
            return load(attach.apply(window, arguments));
          }

          // Use window for now (maybe this?)
          return load(window[attach]);
        });
      });
    },

    write: function(pluginName, moduleName, write, config) {
      if(moduleName in buildMap) {
        var module = buildMap[moduleName];
        var content = module.content;
        var attach = module.attach;
        var def = "define(function() { " + content + ";";

        if(module.attach) {
          if(typeof attach == "function") {
            // convert the attach fn to a string
            var fn = attach.toString();

            // append the file and the logic (body of the attach fn) to attach it.
            def += fn.substring(fn.indexOf("{") + 1, fn.lastIndexOf("}")).trim();
          } else {
            def += "return " + attach + ";";
          }
        }

        // close off the define
        def += "});\n";

        // write module
        write.asModule(pluginName + "!" + moduleName, def);
      }
    }

  };

});