Best Practices

State Classes

• Do use properties instead of fields.
  • Fields are not supported.
• Do use public getters for properties.
  • Using properties with backing fields might break updates.
• Do use private setters for properties.
  • Using private setters prevents accidental mutations.
• Do keep state classes concise feature focused.
  • Keeping state classes small and feature focused improves organization and efficiency.
• Do use read-only value/enumerable types.
  • Using read-only types prevents state mutations.
• Don't use public setters.
  • Public setters allow state to be mutated.
• Don't use overly broad state classes.
  • Overly broad state classes will result in less efficient rebuilds due to their size and number of observers.

Good Example

public class CurrentUser
{
  public int Id { get; private set; }
  public string FirstName { get; private set; } = "Unknown";
  public IEnumerable<string> Permissions { get; private set; } = new List();
}

Bad Example

public class GlobalState
{
  public int _currentUserId { private get; set; }
  public string CurrentUserFirstName { get; set; } = "Unknown";
  public List<string> Permissions { get; set; } = new();

  public int CurrentUserId => _currentUserId;
}

State Updates

• Do use bulk updates whenever more than one property needs to be updated.
  • In order to reduce the number of times observers are invoked.
• Don't update state from within an observer for the same state/property.
  • A state update from within an observer for the same state/property may create an infinite circular invocation loop.
• Don't assign properties with mutable values.
  • State values should be immutable.