More lib files, more functional

Still missing that 'attack' fn, though :(

lib/Tank.ts

@@ -1,4 +1,6 @@
-import { setStats, isLive, isOther, critMultiplier } from "./helpers";
+import { doIf, tap } from "./combinators";
+import { isLive, setProp, dealDamageToRandom, isReadyToAttack } from "./helpers";
+import { mapR, pipe } from "./reducers";
 
 export interface ITank {
   name: string;
@@ -13,16 +15,15 @@ export const buildTank: BuildTank = (name) => ({
   attackDelay: 0,
 } as ITank);
 
-type Attack = (_: ITank[], tank: ITank, tIndex: number, tanks: ITank[]) => ITank[];
+type Attack = (_prevTanks: ITank[], tank: ITank, tIndex: number, tanks: ITank[]) => ITank[];
 const attack: Attack = (_acc, tank, _iTank, tanks) => {
-  // [TODO]: Refactor this imperative block
-  if (tank.attackDelay === 0) {
-    const target = tanks.filter(isOther(tank.name))[Math.floor(Math.random() * tanks.length)];
-    const attackDamage = critMultiplier(tank.health) * tank.health / 100;
-    target.health -= attackDamage;
-  };
-
-  return tanks.map(setStats);
+  tap(
+    doIf(
+      isReadyToAttack,
+      dealDamageToRandom(tanks)
+    )
+  )(tank);
+  return mapR(setProp("attackDelay", tank))(tanks);
 };
 
 type Attacks = (tanks: ITank[]) => ITank[];