How can you restrict users to only read posts where a specific field is set to true using the read access control function?

You can restrict users to read only documents where a specific field is set to true by using a query constraint in the read access control function. For example, if you have a checkbox field named isPublic, you can return a query constraint like this:

const canReadPage = ({ req: { user } }) => {
  if (user) {
    return true; // Allow authenticated users
  }
  // Restrict access to documents where 'isPublic' is true
  return {
    isPublic: {
      equals: true,
    },
  };
};

In this example, authenticated users can access any documents, while unauthenticated users can only access documents where the isPublic field is set to true.