smd.js

(function(exports) {
  var modules = {}
  var factories = {}

  // Require a module by id.
  function require(id) {
    if (!(id in factories)) throw Error(id + ' module is not defined')
    if (!(id in modules)) {
      modules[id] = {}
      factories[id](require, modules[id])
    }
    return modules[id]
  }
  exports.require = require
  require.modules = modules
  require.factories = factories

  // Define a module with id.
  function define(id, factory) {
    if (id in factories) throw new Error(id + ' module is already defined')
    factories[id] = factory
  }
  exports.define = define
})(this)