gistfile1.js

//move queries into a simple object
//to make the more explicit
var queries = {
  getRestaurant: (restaurantId) {
    var query = {
        type: 'select'
      , table: 'restaurants'
      , columns: ['*']
      , where: {id: restaurantId}
    };
    return db.builder.sql(query);
  },
  getCategoriesForRestaurant: (restaurantId) {
    var query = {
      type: 'select'
    , table: 'categories'
    , columns: ['*']
    , where: {restaurant_id: restaurantId}
    , order: {order: 'asc'}
    }
    return db.builder.sql(query);
  },
  getItemsForRestaurant: (restaurantId) {
    var query = {
      type: 'select'
    , table: 'items'
    , columns: ['*']
    , where: {restaurant_id: restaurantId}
    , order: {order: 'asc'}
    }
    return db.builder.sql(query);
  }
};
module.exports.menu = function(req, res) {
  var data = {
    restaurant: null
  , categories: null
  , items: null
  };
  //introduce variable to describe query parameters
  var restaurantId = parseInt(req.params.id);
  
  var tasks = {
    getRestaurant: function(callback) {
      var sql = queries.getRestaurant(restaurantId);
      db.query(sql.query, sql.values, function(error, results) {
        if (error) return res.error(errors.internal.DB_FAILURE, error, callback);
        data.restaurant = results[0];
        return callback();
      });
    }
  , getCategories: function(callback) {
      var sql = queries.getCategoriesForRestaurant(restaurantId);
      db.query(sql.query, sql.values, function(error, results) {
        if (error) return res.error(errors.internal.DB_FAILURE, error, callback);
        data.categories = results;
        return callback();
      });
    }
  , getItems: function(callback) {
      var sql = queries.getCategoriesForRestaurant(restaurantId);
      db.query(sql.query, sql.values, function(error, results) {
        if (error) return res.error(errors.internal.DB_FAILURE, error, callback);
        data.items = results;
        return callback();
      });
    }
  }

  var done = function(error, results) {
    if(error) return;
    var menu = [];
    var categoryIdMenuIndex = {};

    for(var i=0; i<data.categories.length; i++) {
      var category = data.categories[i];
      category.items = [];
      menu.push(category);
      categoryIdMenuIndex[category.id] = i;
    }

    for(var i=0; i<data.items.length; i ++) {
      var item = data.items[i];
      var category = menu[categoryIdMenuIndex[item.category_id]];
      category.items.push(item);
    }
    res.render('menu', {restaurant: data.restaurant, menu: menu}, function(error, html) {
      if (error) return res.error(errors.internal.UNKNOWN, error);
      res.render('index', {content: html}, function(error, html) {
        if (error) return res.error(errors.internal.UNKNOWN, error);
        return res.send(html);
      })
    });
  }

  utils.async.parallel(tasks, done);
}