Javascript – Cloud Firestore – query to get a specific item from a particular document with id

Problem:

Attached is my db structure. How can I get a specific saleOrder item by its id?

Below is my query but it isn’t working.
Thank you in advance.

const ref = collection(db, 'customers', customerId, 'saleOrders');
const q = query(ref, where('id', '==', saleOrderId));
const querySnapshot = await getDocs(q);

Solution:

You’re querying

collection(db, 'customers', customerId, 'saleOrders');

So this is:

• A collection customers, which you have
• A document in there for the customerId, which I assume you have
• A *subcollection under there called saleOrders, which you don’t have

You cannot query a nested map field with a query operator like that. Even if you could, it wouldn’t accomplish anything – as Firestore client-side SDKs always return the full document, not a subset of its fields.

You have a few options:

• Most logically would be to create an actual saleOrders subcollection, store the ID in there as a top-level field, and then query that subcollection as you now do.

• Alternatively you can load the full document you have right now, and filter the sale orders in your client-side code.