Mongoose find all referenced documents

Question

Does mongoose provide a way to find all referenced documents from a previous query' result?

For example:

Product
.find(query)
.exec(function(err, results) {
  ...
  Product
  .find({
    '$or': [
      // get all products where _id is in results.associatedProducts[]
    ]
  })
  ...
});

Answer 1

I wasn't able to find a way to do this natively with mongoose, see below for working solution.

Product
  .find(query)
  .exec(function(err, products) {
    ...
    var associatedSoftware = products.reduce(function(memo, current) {
      if(current.features && current.features.associatedSoftware) {
        return memo.concat(current.features.associatedSoftware.map(function(item) {
          return item._id;
        }));
      }
      return memo;
    }, []);

    Product.find({
      '$or': [
        ...
        { '_id': { '$in': associatedSoftware } }
        ...
      ]
    })
    .exec(function(err, associated) {
      ...
    });
  });

Answer 2

Yes.

You can use query population .

Product
.find(query)
.populate('associatedProducts')
.exec(function(err, results) {
    // ...
});

This will return you an object formatted like this:

var product = {
    foo: bar,
    associatedProducts: [
        // Here are the associated products
        {
            // Product Object
        },
        {
            // Product Object
        },
        {
            // Product Object
        }
    ]
};