LibrarySystem_ver2.html

<script src="TinyTestMod.js"></script>
<script>

(function() {

  var libraryStorage = {};

  function librarySystem(libraryName, array, callback) {
    if (arguments.length > 1) {
      saveLibrary(libraryName, array, callback);
    } else {
      return loadLibrary(libraryName);
    }
  }

  function saveLibrary(libraryName, array, callback) {

    var libraryName = libraryStorage[libraryName] = {};
    var dependencies = libraryName['dependencies'] = array;
    var dependencies_ids = libraryName['dependencies_ids'] = [];

    if (array.length === 0) {
      libraryName['string'] = callback();
    } else {
      for (var i = 0; i < array.length; i++) {
        dependencies_ids.push(uuid()); //generates unique id string for each dependency
      }
      libraryName['string'] = callback.apply(null, dependencies_ids); //saves a string with unique ids, later to be replaced by real values. 
    }
  }

  function loadLibrary(libraryName) {
    if (!libraryStorage[libraryName]) {
      return 'There is no such library'
    } else {
      var libraryName = libraryStorage[libraryName];
      var dependencies = libraryName['dependencies'];
      var dependencies_ids = libraryName['dependencies_ids'];
      var string = libraryName['string'];
      var dependenciesValues = dependencies.map(function(currentValue) {
        if (!libraryStorage[currentValue]) {
          return 'undefined';
        } else {
          return libraryStorage[currentValue]['string'];
        }

      });
      for (var i = 0; i < dependencies_ids.length; i++) {
        string = string.replace(dependencies_ids[i], dependenciesValues[i]) //replaces unique ids with real values
      }
      return string;
    }
  }

  function uuid() {

    var i, random;
    var uuid = '';

    for (i = 0; i < 32; i++) {
      random = Math.random() * 16 | 0;
      if (i === 8 || i === 12 || i === 16 || i === 20) {
        uuid += '-';
      }
      uuid += (i === 12 ? 4 : (i === 16 ? (random & 3 | 8) : random)).toString(16);
    }

    return uuid;
  }

  window.librarySystem = librarySystem;

})();

tests({

  'TEST1: it should save a callback`s return value and return it back if provided with only 1 argument': function() {
    librarySystem('app', [], function() {
      return 'ppapp';
    });
    eq(librarySystem('app'), 'ppapp');
  },

  'TEST2: it should return a string with a `dependency` library value': function() {
    librarySystem('dependency', [], function() {
      return 'loaded dependency';
    });

    librarySystem('app', ['dependency'], function(dependency) {
      return 'app with ' + dependency;
    });

    eq(librarySystem('app'),'app with loaded dependency'); 
  },

  'TEST3: it should accept more than one `dependencies`': function() {
    librarySystem('name', [], function() {
      return 'Gordon';
    });

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

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

    eq(librarySystem('workBlurb'),'Gordon works at Watch and Code'); 
  },

  'TEST4: it should update the library if the value of `dependency` library has changed': function() {
    librarySystem('workBlurb', ['name', 'company'], function(name, company) {
      return name + ' works at ' + company;
    });

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

    librarySystem('company', [], function() {
      return 'Google';
    });

    eq(librarySystem('workBlurb'),'Jake works at Google');
  },

  'TEST5: the callback function for each library should run only once. ': function() {
    var counter = 0;
    librarySystem('test5', ['something'], function(a) {
      counter++;
      return a;
    });
    librarySystem('test5');
    librarySystem('test5');
    librarySystem('test5');
    eq(counter, 1);
  },

});


    
</script>