fix(security & perf): implement bearer session tokens, salted pbkdf2, object pooling and background caching

game/js/systems/combat.js

@@ -1,10 +1,63 @@
+// Particle Object Pool to eliminate GC churn during large waves
+window.ParticlePool = class ParticlePool {
+  constructor(initialCapacity = 150) {
+    this.pool = [];
+    for (let i = 0; i < initialCapacity; i++) {
+      this.pool.push({
+        x: 0,
+        y: 0,
+        vx: 0,
+        vy: 0,
+        color: '#ffffff',
+        size: 3,
+        life: 0,
+        maxLife: 0
+      });
+    }
+  }
+
+  get(x, y, vx, vy, color = '#8bc34a', size = 3, life = 0.35) {
+    const p = this.pool.length > 0 ? this.pool.pop() : { x: 0, y: 0, vx: 0, vy: 0, color: '#ffffff', size: 3, life: 0, maxLife: 0 };
+    p.x = x;
+    p.y = y;
+    p.vx = vx;
+    p.vy = vy;
+    p.color = color;
+    p.size = size;
+    p.life = life;
+    p.maxLife = life;
+    return p;
+  }
+
+  release(p) {
+    if (!p) return;
+    p.life = 0;
+    this.pool.push(p);
+  }
+
+  releaseAll(particles) {
+    if (!Array.isArray(particles)) return;
+    for (let i = 0; i < particles.length; i++) {
+      this.release(particles[i]);
+    }
+  }
+
+  clear() {
+    this.pool = [];
+  }
+};
+
 // Combat & Collision Resolution System (with Bowling Ricochet & Coin Drops)
 window.CombatSystem = class CombatSystem {
   constructor() {
+    this.particlePool = new window.ParticlePool(150);
     this.particles = [];
   }
 
   reset() {
+    if (this.particlePool) {
+      this.particlePool.releaseAll(this.particles);
+    }
     this.particles = [];
   }
 
@@ -12,45 +65,50 @@ window.CombatSystem = class CombatSystem {
     for (let i = 0; i < count; i++) {
       const angle = Math.random() * Math.PI * 2;
       const speed = 40 + Math.random() * 80;
-      this.particles.push({
+      this.particles.push(this.particlePool.get(
         x,
         y,
-        vx: Math.cos(angle) * speed,
-        vy: Math.sin(angle) * speed,
+        Math.cos(angle) * speed,
+        Math.sin(angle) * speed,
         color,
-        size: 3 + Math.random() * 3,
-        life: 0.35,
-        maxLife: 0.35
-      });
+        3 + Math.random() * 3,
+        0.35
+      ));
     }
   }
 
   createExplosionParticles(x, y) {
+    const colors = ['#ff5722', '#ff9800', '#ffeb3b', '#424242'];
     for (let i = 0; i < 35; i++) {
       const angle = Math.random() * Math.PI * 2;
       const speed = 50 + Math.random() * 200;
-      const colors = ['#ff5722', '#ff9800', '#ffeb3b', '#424242'];
-      this.particles.push({
+      this.particles.push(this.particlePool.get(
         x,
         y,
-        vx: Math.cos(angle) * speed,
-        vy: Math.sin(angle) * speed,
-        color: colors[Math.floor(Math.random() * colors.length)],
-        size: 5 + Math.random() * 8,
-        life: 0.65,
-        maxLife: 0.65
-      });
+        Math.cos(angle) * speed,
+        Math.sin(angle) * speed,
+        colors[Math.floor(Math.random() * colors.length)],
+        5 + Math.random() * 8,
+        0.65
+      ));
     }
   }
 
   update(dt, gameState) {
-    // 1. Update Particles
-    for (const p of this.particles) {
+    // 1. Update Particles in-place (eliminating GC allocations)
+    let writeIdx = 0;
+    for (let i = 0; i < this.particles.length; i++) {
+      const p = this.particles[i];
       p.x += p.vx * dt;
       p.y += p.vy * dt;
       p.life -= dt;
+      if (p.life > 0) {
+        this.particles[writeIdx++] = p;
+      } else {
+        this.particlePool.release(p);
+      }
     }
-    this.particles = this.particles.filter(p => p.life > 0);
+    this.particles.length = writeIdx;
 
     // 2. Projectiles vs Zombies
     for (const proj of gameState.projectiles) {
@@ -233,16 +291,15 @@ window.CombatSystem = class CombatSystem {
     // Tree of Wisdom Cheat: Daisies
     if (gameState.tree && gameState.tree.cheats && gameState.tree.cheats.daisies) {
       for (let i = 0; i < 6; i++) {
-        this.particles.push({
-          x: zombie.x + (Math.random() - 0.5) * 30,
-          y: zombie.y + 10 + (Math.random() - 0.5) * 16,
-          vx: 0,
-          vy: -8,
-          color: '#ffffff',
-          size: 4,
-          life: 2.5,
-          maxLife: 2.5
-        });
+        this.particles.push(this.particlePool.get(
+          zombie.x + (Math.random() - 0.5) * 30,
+          zombie.y + 10 + (Math.random() - 0.5) * 16,
+          0,
+          -8,
+          '#ffffff',
+          4,
+          2.5
+        ));
       }
     }