refactor: create strongly type metadata property on Actor and Player

Author: Jameskmonger

src/engine/world/actor/actor.ts

@@ -16,6 +16,7 @@ import { Pathfinding } from './pathfinding';
 import { Attack, AttackDamageType } from './player/attack';
 import { Behavior } from './behaviors';
 import { Effect, EffectType } from './effect';
+import { ActorMetadata } from './metadata';
 
 
 export type ActorType = 'player' | 'npc';
@@ -33,7 +34,16 @@ export abstract class Actor {
     public readonly inventory: ItemContainer = new ItemContainer(28);
     public readonly bank: ItemContainer = new ItemContainer(376);
     public readonly actionPipeline = new ActionPipeline(this);
-    public readonly metadata: { [key: string]: any } = {};
+
+    /**
+     * The map of available metadata for this actor.
+     *
+     * You cannot guarantee that this will be populated with data, so you should always check for the existence of the
+     * metadata you are looking for before using it.
+     *
+     * @author jameskmonger
+     */
+    public readonly metadata: Partial<ActorMetadata> = {};
 
     /**
      * @deprecated - use new action system instead

src/engine/world/actor/metadata.ts

@@ -0,0 +1,10 @@
+/**
+ * The definition of the metadata available on an {@link Actor}.
+ *
+ * You cannot guarantee that all of these properties will be present on an actor,
+ * so you should always check for their existence before using them.
+ *
+ * @author jameskmonger
+ */
+export type ActorMetadata = {
+};

src/engine/world/actor/player/metadata.ts

@@ -0,0 +1,12 @@
+/**
+ * The definition of the metadata directly available on a {@link Player}.
+ *
+ * This is a subset of the metadata available on an {@link Actor}. See {@link ActorMetadata} for more information.
+ *
+ * You cannot guarantee that all of these properties will be present on an actor,
+ * so you should always check for their existence before using them.
+ *
+ * @author jameskmonger
+ */
+export type PlayerMetadata = {
+};

src/engine/world/actor/player/player.ts

@@ -45,6 +45,7 @@ import { dialogue } from '../dialogue';
 import { Npc } from '../npc';
 import { combatStyles } from '../combat';
 import { SkillName } from '../skills';
+import { PlayerMetadata } from './metadata';
 
 
 export const playerOptions: { option: string, index: number, placement: 'TOP' | 'BOTTOM' }[] = [
@@ -117,6 +118,18 @@ export class Player extends Actor {
     public cutscene: Cutscene = null;
     public playerEvents: EventEmitter = new EventEmitter();
 
+    /**
+     * Override the Actor's `metadata` property to provide a more specific type.
+     *
+     * You cannot guarantee that this will be populated with data, so you should always check for the existence of the
+     * metadata you are looking for before using it.
+     *
+     * The ! is used to tell the compiler that we know this property will be defined.
+     *
+     * @author jameskmonger
+     */
+    public readonly metadata!: (Actor['metadata'] & Partial<PlayerMetadata>);
+
     private readonly _socket: Socket;
     private readonly _inCipher: Isaac;
     private readonly _outCipher: Isaac;