(function() {
  	var libraryStorage = {};
  	function librarySystem(libraryName, dependencies, callback) {

  	  // creating a library
      if(arguments.length > 1) {

        // creating a dependent library
    	if(dependencies && dependencies.length !== 0) {
    	  var requiredLibrariesStorage = [];

    	  for(var i = 0; i < dependencies.length; i++) {
    	  	requiredLibrariesStorage.push(libraryStorage[dependencies[i]]);
    	  }

    	  libraryStorage[libraryName] = callback.apply(this, requiredLibrariesStorage)
  	    } else {
  	      // creating an independent library
		  libraryStorage[libraryName] = callback();
  	    }
      } else {
      // retreiving a library
      	return libraryStorage[libraryName];
      }
  	}
  	  window.librarySystem = librarySystem;
  })();



  librarySystem('name', [], function() {
    return 'Gordon';
  });

  librarySystem('company', [], function() {
    return 'Watch and Code';
  });

  librarySystem('workBlurb', ['name', 'company'], function(name, company) {
    return name + ' works at ' + company;
  });

  console.log(librarySystem('workBlurb')); // 'Gordon works at Watch and Code'