Refactor to extract a responsibility

Co-authored-by: Janne Savolainen <janne.savolainen@live.fi>

Signed-off-by: Iku-turso <mikko.aspiala@gmail.com>

packages/kata-for-gabriel/src/handle-landed-hit-on-monster-for.ts

@@ -0,0 +1,33 @@
+import type { Dependencies } from "./monster-beatdown";
+
+export type Monster = {
+  hitPoints: number;
+};
+
+export const handleLandedHitOnMonsterFor =
+  ({
+     monster,
+     messageToPlayer,
+   }: {
+    monster: Monster;
+    messageToPlayer: Dependencies["messageToPlayer"];
+  }) =>
+    () => {
+      monster.hitPoints--;
+
+      if (monster.hitPoints) {
+        messageToPlayer(
+          `You successfully land a hit on the monster, and it now only has ${monster.hitPoints} hit-points remaining.`,
+        );
+
+        return { monsterIsDead: false };
+      }
+
+      messageToPlayer(
+        "You successfully land a final hit on the monster, and it is now properly beat.",
+      );
+
+      messageToPlayer("You win. Congratulations!");
+
+      return { monsterIsDead: true };
+    };

packages/kata-for-gabriel/src/monster-beatdown.ts

@@ -1,14 +1,19 @@
+import { handleLandedHitOnMonsterFor, Monster } from "./handle-landed-hit-on-monster-for";
+
 export type Dependencies = {
   messageToPlayer: (message: string) => void;
   questionToPlayer: (message: string) => Promise<boolean>;
   castDie: () => Promise<number>;
 };
 
-const createGame = ({ messageToPlayer, questionToPlayer, castDie }: Dependencies) => ({
+const createGame = ({ messageToPlayer, questionToPlayer, castDie }: Dependencies) => {
-  start: async () => {
+  const monster: Monster = { hitPoints: 3 };
-    let monsterHitPoints = 3;
 
-    messageToPlayer(`You encounter a monster with ${monsterHitPoints} hit-points`);
+  const handleLandedHitOnMonster = handleLandedHitOnMonsterFor({ messageToPlayer, monster });
+
+  return {
+    start: async () => {
+      messageToPlayer(`You encounter a monster with ${monster.hitPoints} hit-points`);
 
       const playerWantsToAttack = await questionToPlayer("Attack the monster?");
       if (!playerWantsToAttack) {
@@ -28,24 +33,13 @@ const createGame = ({ messageToPlayer, questionToPlayer, castDie }: Dependencies
 
         const playerLandsHitOnMonster = dieResult > 3;
         if (playerLandsHitOnMonster) {
-        monsterHitPoints--;
+          const { monsterIsDead } = handleLandedHitOnMonster();
-
+          if (monsterIsDead) {
-        if (!monsterHitPoints) {
-          messageToPlayer(
-            "You successfully land a final hit on the monster, and it is now properly beat.",
-          );
-
-          messageToPlayer("You win. Congratulations!");
-
             return;
           }
-
-        messageToPlayer(
-          `You successfully land a hit on the monster, and it now only has ${monsterHitPoints} hit-points remaining.`,
-        );
         } else {
           messageToPlayer(
-          `You fail to land a hit on the monster, and it still has ${monsterHitPoints} hit-points remaining.`,
+            `You fail to land a hit on the monster, and it still has ${monster.hitPoints} hit-points remaining.`,
           );
         }
 
@@ -62,6 +56,8 @@ const createGame = ({ messageToPlayer, questionToPlayer, castDie }: Dependencies
         }
       }
     },
-});
+  };
+};
 
 export { createGame };
+