Created a lib folder for custom function

lib/helpers.ts

@@ -0,0 +1,17 @@
+import { ITank } from "./Tank";
+
+type CritMultiplier = (health: number) => number;
+export const critMultiplier: CritMultiplier = (health) =>
+  Math.floor(Math.random() * 10) >= 10 - health / 10 ? 1 : 2;
+
+type SetStats = (tank: ITank) => ITank;
+export const setStats: SetStats = (tank) => ({
+  ...tank,
+  attackDelay: tank.attackDelay === 0 ? Math.floor(tank.health / 10) : tank.attackDelay - 1,
+} as ITank);
+
+type IsLive = (tank: ITank) => boolean;
+export const isLive: IsLive = (tank) => tank.health >= 0;
+
+type IsOther = (name: string) => (tank: ITank) => boolean;
+export const isOther: IsOther = (name) => (tank) => tank.name !== name;