singleton for requirejs

gistfile1.js

   _.mixin({
       singleton:function(Constructor, scope) {
        var instance;
        return function(settings) {
            var args = _.toArray(arguments);
            var wrapper = function(f, params) {
                 var params = [f];
                    params = params.concat(args);
                    return f.bind.apply(f, params);
            };
            if (_.isObject(settings) && settings.singleton && instance) {
                return instance;
            } else {
                instance = new (wrapper(Constructor, args));
                return instance;
            }
        };
      }
   });
  define(['module'], function(module) {
    return _.singleton(module);
  });

downside is that you have to have es5 bind and i dont know how to release the models from memory