Move logic that maps item names to Update behavior to a new resolver file

TypeScript/app/gilded-rose.ts

@@ -1,5 +1,5 @@
 import { Item } from "@app/item";
-import { IUpdateBehavior, LegacyBehavior } from "@app/update-behaviors";
+import { getUpdateBehaviorFor } from "@app/update-behaviors";
 
 export class GildedRose {
   // also can't edit this because of the kata rules.
@@ -12,14 +12,7 @@ export class GildedRose {
 
   updateQuality() {
     return this.items.map((item) => {
-      return this.#getUpdateBehaviorFor(item).update();
+      return getUpdateBehaviorFor(item).update();
     });
   }
-
-  #getUpdateBehaviorFor(item: Item): IUpdateBehavior {
-    switch (item.name) {
-      default:
-        return new LegacyBehavior(item);
-    }
-  }
 }

TypeScript/app/update-behaviors/behavior-resolver.ts

@@ -0,0 +1,10 @@
+import { Item } from "@app/item";
+import { IUpdateBehavior } from "./update-behavior.interface";
+import { LegacyBehavior } from "./legacy-behavior";
+
+export function getUpdateBehaviorFor(item: Item): IUpdateBehavior {
+  switch (item.name) {
+    default:
+      return new LegacyBehavior(item);
+  }
+}

TypeScript/app/update-behaviors/index.ts

@@ -1,2 +1,2 @@
 export * from "./update-behavior.interface";
-export * from "./legacy-behavior";
+export * from "./behavior-resolver";