ddd example

ddd.js

/*
High level directory structure

root/
    application/    (configuration)
    domain/         (business logic)
      Entities/     (User, Article, Image, Video)
        Aggregates/ (UserProfile, UserHistory)
      ValueObjects/ 
    dataAccess/     (repositories for data retrieval/persistance)
    services/       (manages of domain and dataAccess)

*/

//Application Layer - application/configuration.js

configuration.article.databaseImplementation.default = "breeze mongo";
configuration.article.databaseImplementation.search = "elasticsearch";

//Service Layer - services/articleService.js

function getArticles(req, res){
  var articleRepository = getArticleRepository(req);
  articleRepository.getArtcles(req, res);
}

function getArticleRepository(req){
  //Need to decide if we should go through elasticsearch or breeze
  if(req.query.search) // /api/article?search=1
    return articleRepositoryFactory.get(configuration.article.databaseImplementation.search);
  else
    return articleRepositoryFactory.get(configuration.article.databaseImplementation.default);
}

//Data Access Layer - dataAccess/articleRepositoryFactory.js

function get(implementation){
  switch(implementation){
    case 'breeze mongo':
      return articleRepositoryBreeezeMongo;
    case 'mongoose mongo':
      return articleRepositoryMongooseMongo;
    case 'elasticsearch':
      return articleRepositoryElasticsearch;
    case 'redis':
      return articleRepositoryRedis;
    case 'mysql':
      return articleRepositoryMysql;
    case 'memcache':
      return articleRepositoryMemcache;
  }
}

//Data Access Layer

//dataAccess/articleRepositoryBreeezeMongo.js

function getArticles() { /* perform a breeze query to mongo - return JSON */ }

//dataAccess/articleRepositoryMongooseMongo.js

function getArticles() { /* perform a mongoose ODM query to mongo - return JSON  */ }

//dataAccess/articleRepositoryElasticsearch.js

function getArticles() { /* perform a query to elasticsearch - return JSON  */ }



//Domain Layer (business logic)
/*
  Domains:
    Search     (score calculation)
    Objectives (point/token calculation)
    Chat       (Rooms, Members)
    Authentication
    Authorization

*/