Firestore Security Rules - Update one specific field without providing data for the other fields

Question

I'm new to Firestore and it's security rules. For my project, I have some simple rules for data validation that looks like this:

match /users/{userId} {
    allow create, update: if
        request.resource.data.name is string &&
        request.resource.data.age is int &&
        request.resource.data.score is int;
}

At the moment I have only tested it on the simulator and it works fine in terms of validating the data, but the problem is for each query I have to provide data for all fields/keys mentioned in the rules. For example, if I want to update the name of the user, I also need to provide the age and score data.

How should I structure my rules so it's possible to update only one specific field without providing data for the other fields?

Answer 1

You can use get() to get a field and set a default value if it doesn't exist as shown below:

match /users/{userId} {
  allow create, update: if
    request.resource.data.get("name", "") is string &&
    request.resource.data.get("age", 0) is int &&
    request.resource.data.get("score", 0) is int;
  }
}

Checkout enforcing types for optional fields section in the documentation.