getting values of array of ids from another table

Question

I am new to node and noSQL databases and am having trouble understanding how to pass an array of id's and find the values using the id in another table. I have two tables 'users' and products'. The 'users' table looks something like:

 {

    "_id":ObjectId("54925687fd6s87f6dsf8"),
    "products":[ObjectId("fdsfdsa33f"),ObjectId("fdsa4grf4g6"), etc..]
}

The products table something like:

{
   "_id":ObjectId("fdsfdsa33f")
   "color":red
   "size":large
}

I would like to understand how I can get the values of only the products whose ID is in the users.products array and send that through a route to use in my jade template. Thanks in advance!

Right now I can do it, but can only get one of the array values at a time using

    router.get('/dashboard', utils.requireLogin, function(req, res) {
       models.Product.findOne({ _id: req.user.product[2] }, 'color size', function(err, doc) {
          if(err){return console.error(err)}else{
          console.log(doc.name);
          var prop = doc.name;
          res.render('dashboard.jade', {prop : prop});
     }
   });
});

And my jade file:

block body 
  .container
    .col-md-6
      h1 Manage Properties
      if user.products.length == 0
          p No Products
      else
        each prod, i in user.products
          li #{prop.color}
          li #{prop.size}

I understand I have to manually set the array number but would like to pass all the ids and get a callback of all the product information.

The SQL equivalent of what I am looking for would be something like:

for(var i=0; i<user.products.length;i++){
  SELECT * FROM products WHERE id = user.products[i]
}

Answer 1

You can achieve this with the populate method of a Mongoose model instance:

router.get('/dashboard', utils.requireLogin, function(req, res) {
  models.User
    // this assumes the id is stored in user.id
    .findOne({ _id: req.user.id })
    // populate the 'products' field using the ids in the array
    .populate('products')
    .exec(function(err, user) {
      // The products can be found in the user.products property
      user.products;
    });
});