Catbug, Engine, Pickup: use null instead of empty object, cleaner initialization for non-function properties

Catbug.js

@@ -1,11 +1,13 @@
-var catbug = {};
-catbug.x = 45;
-catbug.y = 90;
-catbug.vX = 0;
-catbug.vY = 0;
-catbug.frame = 0;
-catbug.HP = 3;
-catbug.maxHP = 3;
+var catbug = {
+  x: 45,
+  y: 90,
+  vX: 0,
+  vY: 0,
+  frame: 0,
+  HP: 3,
+  maxHP: 3
+};
+
 catbug.move = function()
 {
   this.x += this.vX;

Engine.js

@@ -100,7 +100,7 @@ renderer.drawPickups = function()
   var i;
   for (i = 0; i < 10; i++)
   {
-    if (!isEmptyObject(stuff[i])){
+    if (stuff[i] != null){
       screen.drawImage(stuff[i].sprite, stuff[i].x, stuff[i].y);}
   }
 }
@@ -136,20 +136,6 @@ controller.left = false;
 controller.space = false;
 controller.q = false;
 
-function isEmptyObject(obj)
-{
-  var name;
-  for (name in obj)
-  {
-    if (obj.hasOwnProperty(name))
-    {
-      return false;
-    }
-  }
-  return true;
-}
-
-
 function scoreSummary()
 {
   gameState.frame = thisFrame;
@@ -191,7 +177,7 @@ function resetGame()
   catbug.vY = 0;
   gameState.points = 0;
   gameState.threshold = 10;
-  stuff = [{}, {}, {}, {}, {}, {}, {}, {}, {}, {}];
+  stuff = new Array(10);
 }
 
 function loop()
@@ -346,4 +332,4 @@ function releaseHandler(e)
     default:
       break;
   }
-}
+}

Pickup.js

@@ -43,25 +43,27 @@ function managePickups()
   else genSpeed = Math.floor(Math.random()*10);
   for (i = 0; i < 10; i++)
   {
-    if (!isEmptyObject(stuff[i]))
+    if (stuff[i] != null)
     {
       movePickup(stuff[i]);
       if (stuff[i].x < -32)
       {
-        stuff[i] = {};
+        stuff[i] = null;
         catbug.HP--;
       }
       else
       {
-        var box = {};
-        box.x = stuff[i].x;
-        box.y = stuff[i].y;
-        box.w = 36;
-        box.h = 36;
+        box = {
+          x: stuff[i].x,
+          y: stuff[i].y,
+          w: 36,
+          h: 36
+        }
+        
         if (catbug.isInRect(box))
         {
         getPickup(stuff[i]);
-        stuff[i] = {};
+        stuff[i] = null;
         }
       }
     }
@@ -96,4 +98,4 @@ function getPickup(self)
     catbug.HP = catbug.maxHP;
   }
   
-}
+}