Tried to make the logic simpler while maintaining O(1) time complexity

Author: vasiIix

src/herbivoresAndCarnivores.js

@@ -1,41 +1,71 @@
 'use strict';
 
 class Animal {
+  /**
+  static createAliveAnimalList() {
+    const alive = [];
+    const emptyslots = [];
+
+    const list = alive;
+
+    list.add = (animal) => {
+      if (emptyslots.length === 0) {
+        animal.index = alive.push(animal) - 1;
+      } else {
+        const index = emptyslots.pop();
+
+        animal.index = index;
+        alive[index] = animal;
+      }
+    };
+
+    list.remove = (animal) => {
+      alive[animal.index] = null;
+      emptyslots.push(animal.index);
+    };
+
+    return list;
+  }
+
+  static alive = Animal.createAliveAnimalList();
+*/
+
   static alive = [];
-  static emptyslots = [];
+  static #emptyslots = [];
+
   constructor(name, health = 100) {
     this.name = name;
     this._health = health;
-    this.isalive = true;
+    this.addToAlive();
+  }
 
-    if (Animal.emptyslots.length === 0) {
-      this.index = Animal.alive.push(this) - 1;
-    } else {
-      const index = Animal.emptyslots.pop();
+  addToAlive() {
+    if (Animal.#emptyslots.length > 0) {
+      this.index = Animal.#emptyslots.pop();
+      Animal.alive[this.index] = this;
 
-      this.index = index;
-      Animal.alive[index] = this;
+      return;
     }
-  }
 
+    this.index = Animal.alive.length;
+    Animal.alive.push(this);
+  }
   get health() {
     return this._health;
   }
-
   set health(value) {
     this._health = value;
 
     if (this._health <= 0) {
-      this.isalive = false;
       this.die();
     }
   }
-  getHeart(value) {
+  takeDamage(value) {
     this.health -= value;
   }
   die() {
     Animal.alive[this.index] = null;
-    Animal.emptyslots.push(this.index);
+    Animal.#emptyslots.push(this.index);
   }
 }
 
@@ -52,11 +82,11 @@ class Herbivore extends Animal {
 
 class Carnivore extends Animal {
   bite(animal) {
-    if (animal instanceof Carnivore || animal.hidden) {
+    if (!(animal instanceof Herbivore) || animal.hidden) {
       return;
     }
 
-    animal.getHeart(50);
+    animal.takeDamage(50);
   }
 }