DTO conventions

A DTO is a plain C# class whose shape gets serialised across the bridge. DTOs are used as:

• Event payload types: Event<DamageEvent>.
• Nested state: a [BridgeState] property of type Observable<PlayerStats> where PlayerStats is itself a class with its own observable members.
• Action parameter types: [BridgeAction] public void Submit(SubmissionData data).

Rules

1. Public class. public class FooEvent { ... }. No structs (yet — structs may be added in a future ABI revision).

2. Public fields or auto-properties. The serialiser walks public fields and auto-properties. Private members are ignored.

   public class DamageEvent {
     public float Amount;
     public bool  IsCritical;
   }

3. Supported field types:

   • Primitives: int, long, float, double, bool
   • string
   • Enums (serialised as their underlying integer)
   • List<T> of supported types
   • Other DTOs

4. No constructor logic that matters. The deserialiser uses the parameterless constructor (or none) and sets fields. If you put logic in a constructor, it does not run on the UI side.

5. No reference loops. DTOs are serialised as a tree. If two DTOs reference each other, the serialiser stack-overflows.

Naming

The TypeScript type generator translates C# names to TS using the same casing rules as bridge members:

• C# DamageEvent → TS DamageEvent.
• C# Amount field → TS amount.
• C# IsCritical field → TS isCritical.
• Acronyms stay as a unit: C# HudVisible → TS hudVisible, but C# HUDSettings → TS hudSettings.

A worked example

public class InventoryItem {
  public string Id;
  public int    Quantity;
}

public class PlayerLoadout {
  public List<InventoryItem> Items;
  public string              Weapon;
}

[Bridge]
public partial class GameBridge {
  [BridgeState] public Observable<PlayerLoadout> Loadout { get; } = new(new PlayerLoadout {
    Items = new(),
    Weapon = "shortsword",
  });
}

The generated TS:

interface InventoryItem { id: string; quantity: number }
interface PlayerLoadout { items: InventoryItem[]; weapon: string }

bridge.state.loadout  // PlayerLoadout, reactive