Firestore query subcollections

Question

I thought I read that you can query subcollections with the new Firebase Firestore, but I don\'t see any examples. For example I have my Firestore setup in the following way

Answer 1

What if you store songs as an object instead of as a collection? Each dance as, with songs as a field: type Object (not a collection)

{
  danceName: "My Dance",
  songs: {
    "aNameOfASong": true,
    "aNameOfAnotherSong": true,
  }
}

then you could query for all dances with aNameOfASong:

db.collection('Dances')
  .where('songs.aNameOfASong', '==', true)
  .get()
  .then(function(querySnapshot) {
    querySnapshot.forEach(function(doc) {
      console.log(doc.id, " => ", doc.data());
    });
   })
   .catch(function(error) {
     console.log("Error getting documents: ", error);
    });