add ability to move from room to room.

Scene.ts

@@ -3,14 +3,55 @@
  */
 
 import type { Exit, StoryScene, Item, SceneProperties } from "./types.ts";
-import Vessel from "./Vessel.ts";
+import Entity from "./Entity.ts";
 
-// The Scene is a type of "Vessel" which is a generic object that can have effects
+// The Scene is a type of "Entity" which is a generic object that can have effects
 // and items.
-export default class Scene extends Vessel<SceneProperties> {
-	constructor(gameData: StoryScene<SceneProperties>) {
-		// TODO: [] is a placeholder for scene effects.
-		super(gameData.properties, gameData.conditions);
+export default class Scene extends Entity<SceneProperties> {
+	protected _map: StoryScene<SceneProperties>[];
+	protected _identifier: string;
+
+	constructor(identifier: string, map: StoryScene<SceneProperties>[]) {
+		const scene = Scene.getScene(identifier, map);
+
+		if (!scene) {
+			throw new Error("cannot find scene!");
+		}
+
+		const { properties, conditions } = scene;
+
+		super(properties, conditions);
+
+		this._identifier = identifier;
+		this._map = map;
+	}
+
+	changeScene(identifier: string) {
+		const scene = Scene.getScene(identifier, this._map);
+
+		if (scene) {
+			const { conditions, properties } = scene;
+
+			this.properties = properties;
+			this.conditions = conditions;
+		}
+	}
+
+	// get removes an items from the scene and returns it
+	get(target: string): Item | null {
+		const { items = [] } = this._properties;
+		const idx = items.findIndex(({ name }) => name === target);
+
+		// if we found an index for the given item
+		if (idx >= 0) {
+			const item = items[idx];
+			items.splice(idx, 1);
+
+			return item;
+		}
+
+		// if an item wasn't found and returned, return null
+		return null;
 	}
 
 	// look returns a string that describes the scene and the items in it
@@ -41,23 +82,6 @@ export default class Scene extends Vessel<SceneProperties> {
 		return fullDescription;
 	}
 
-	// get removes an items from the scene and returns it
-	get(target: string): Item | null {
-		const { items = [] } = this._properties;
-		const idx = items.findIndex(({ name }) => name === target);
-
-		// if we found an index for the given item
-		if (idx >= 0) {
-			const item = items[idx];
-			items.splice(idx, 1);
-
-			return item;
-		}
-
-		// if an item wasn't found and returned, return null
-		return null;
-	}
-
 	// Turn exits into a string description with an "and" separating the last two items
 	private static describeExits(exits: Exit[]) {
 		const exitDescriptions = exits.map(({ description }) => description);
@@ -74,4 +98,12 @@ export default class Scene extends Vessel<SceneProperties> {
 			return `${restExits.join(", ")} and ${lastExit}`;
 		}
 	}
+
+	// This needs to be static so that we can use it in the constructor
+	private static getScene(
+		identifier: string,
+		map: StoryScene<SceneProperties>[]
+	): StoryScene<SceneProperties> | null {
+		return map.find((scene) => scene.identifier === identifier) || null;
+	}
 }