I am pushing on object into my ROOMS array with .on("child_added", ....) as below.  One of the parts of that object is an array of other objects (Player obj which has some properties like id, name, and so on).  How do i assign to ROOMS.players because snap.child("players").val() does not work (EXCEPTION: Error trying to diff '[object Object]')  snap.child("players").val() structure looks something like this:
-rooms
   -id
   -name
   -isRoomFull
   +board
   -players
      -kEFvdfeff84fdfdff
          -id
          -name
      -kEFvd4545dfjh9fvv
          -id
          -name
getRooms() {
this.roomsRef.on("child_added", function(snap) {
    ROOMS.push({
        id: snap.child("id").val(),
        name: snap.child("name").val(),
        players: [], //how to assign to this property
        isRoomFull: snap.child("isRoomFull").val(),
        board: snap.child("board").val(),
    })
});
 
     
    