nested-populate.js

// Example:
// User has an array of references to posts
// Posts have an array of references to comments

// Or Dani's example: https://github.com/webmad-shared/doublepopulate/blob/master/bin/seeds.js

router.get('/posts', (req, res, next) => {
  Model.find()
        .populate('oneProperty') // .populate("creator")
        .populate({
          path:'secondProperty', // .populate("comments")
          populate:{
            path:'author', // what are we populating inside "comments"
            model:'User'// the property we are populating is actually which model
         }
  })
  .then(x => res.send(x))
  .catch(err => res.send(err))
});