Using Firebase Firestore, I have a data structure that looks like this:

rooms{ 
    room1 {
         datum : string
         people { 
               person1 {
                      name : string
                      aliases {
                             x : string

A root collection, rooms

A child doc, room1

A grand-child collection, people,

A grand-child doc, person1

A great-grandchild collection, aliases

I'm using Angular and Firebase for my app. I'm trying to update the grandchild collection, aliases. The first step I'm taking is to access that collection; this is what I've tried so far:

people = this.firestore
      .collection("rooms")
      .doc("room1")
      .collection("people").snapshotChanges();
people.subscribe(item =>{
      console.log(item)
})

The issue is, nothing is ever returned. I know it's not due to waiting for the subscription because I put the subscribe / console.log component in a button, put the snapshot changes component in ngOnInit, and still got nothing regardless of how long I waited.

Technically, the 'people' collection is an array inside the room1 doc, not necessarily a sub-collection. How do I properly access grandchild data structures with firebase?