JavaScript Design Patterns

module.js

var options = {
  username: 'blah',
  server: '127.0.0.1'
};

var ConfigObject = (function(params) {

  var username = params.username || '',
      server = params.server || '',
      password = params.password || '';

      function _checkPassword() {
        if (this.password === '') {
          console.log('no password!');
          return false;
        }
        return true;
      }

      function _checkUsername() {
        if (this.username === '') {
          console.log('no username!');
          return false;
        }
        return true;
      }

      function login() {
        if (_checkPassword() && _checkUsername()) {
          // perform login
        }
      }

  return {
    login: login
  }

})(options);

prototype.js

function Hello (greeting) {
  this.greeting = greeting || 'Hello World!'; 
}

Hello.prototype.speak = function(somethingElse) { 
  var message = somethingElse || this.greeting;
  console.log(message); 
}

var hi = new Hello('Just saying hi!');

hi.speak();
hi.speak('Something different');

var hello = new Hello();
hello.speak();
hello.speak('Yep');

singleton.js

var GlobalConfigurationObject = (function() {
  var instance; 
  function createInstance() {
    return new ConfigObject();
  };

  var getInstance = function() {
    if (!instance) {
      instance = createInstance();
    }
    return instance;
  }

  return {
    getInstance: getInstance
  }
})();