Firestore update document with WHERE

Question

async () => {
const doc = await firestore().collection("queue").where("order_id", "==", elem.orderID)
}

Here is the code of mine. The question is, how to update a document without knowing its document ID. Is it feasible by a query?

Answer 1

With firestore().collection("queue").where("order_id", "==", elem.orderID) you just define a Query but you don't fetch any data.

I make the assumption that this query will return a unique document. Therefore you need to execute the Query with the get() method and, then, update the unique document returned by the Query, as follows:

async () => {
  const querySnapshot = await firestore().collection("queue").where("order_id", "==", elem.orderID).get();
  await querySnapshot.docs[0].ref.update({...})
}

Note how we use the docs property of the QuerySnapshot which returns "an array of all the documents in the QuerySnapshot."