Watch and Code librarySystem with dependencies

librarySystem_with_dependencies.js

 (function() {
  var libraryStorage = {};

  function librarySystem(library, dependencyArray, callback) {
    var libraries = [];
    if ( arguments.length > 1 ) {
      // go through dependencyArray and get the actual libraries
      dependencyArray.forEach(function(dependency) {
        libraries.push(libraryStorage[dependency]);
      });
      
      libraryStorage[library] = callback.apply(this, libraries);
    } else {
      return libraryStorage[library];
    }
  }

  window.librarySystem = librarySystem;
})();