Firestore: How to query a map object inside a collection of documents?

Question

My objective:

The web app (similar to Google Drive) has 2 screens.

First screen is 'My Story' which displays all the story documents whom I'm the owner.

Second screen is 'Shared with me' which displays all the story documents that I'm either reader, writer, or commenter.

We have this /stories/{storyid}

{
  title: "A Great Story",
  content: "Once upon a time ...",
  roles: {
    alice: "owner",
    bob: "reader",
    david: "writer",
    jane: "commenter"
    // ...
  }
}

Full data structure reference: https://firebase.google.com/docs/firestore/solutions/role-based-access

Question: How to write the below query to fulfil the above objective?

db
.collection('stories')
.where(`roles.${uid}`, '==', 'owner')

The above query does NOT work because it will require Firestore to index roles.alice, roles.bob, roles.david, roles.jane, and roles.[all_uid].

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Edit #1: Found a related post (with no answers) asking about Firestore querying with roles

Answer 1

Now you can filter ...

db
  .collection('orders')
  .where('orderDetails.status', '==', 'OPEN')

It will check if field orderDetails at property status equals to 'OPEN'

Answer 2

Please let me know if I'm mistaken, but it appears that your query should actually work. as an experiment I added the structure you gave in the question and performed the query successfully in the firebase console.

Is this not what you are going for? I also made sure that the "in" operator works for this case as well. In this way you could ask which stories the user is owner & commenter.

This pulls in the correct results: