Query documents in Mongoose

// find each person with a last name matching 'Ghost'
var query = Person.findOne({ 'name.last': 'Ghost' });

// selecting the `name` and `occupation` fields
query.select('name occupation');

// execute the query at a later time
query.exec(function (err, person) {
  if (err) return handleError(err);
  // Prints "Space Ghost is a talk show host."
  console.log('%s %s is a %s.', person.name.first, person.name.last,
    person.occupation);
});

References
https://mongoosejs.com/docs/queries.html