adding 502 error

games/space-invaders502/js/update.js

@@ -0,0 +1,45 @@
+
+// Update game objects
+var update = function (modifier) {
+	controls(modifier);
+
+  for (var i = 0; i< playerShots.length; i++){
+    var shot = playerShots[i];
+    shot.y = shot.y - modifier * shotSpeed;
+
+    for (var e= 0; e < enemies.length; e++){
+      var enemy = enemies[e];
+      if (collision(shot, enemy)) {
+        console.log("Collision with enemy ", shot, enemy);
+        playerShots.splice(i, 1);
+        enemies.splice(e, 1);
+        break;
+      }
+    }
+  }
+
+  for (var i = 0; i< enemyShots.length; i++){
+    var shot = enemyShots[i];
+    shot.y = shot.y + modifier * shotSpeed;
+
+      if (collision(shot, hero)) {
+        console.log("Collision with hero ", shot, hero);
+        enemyShots.splice(i, 1);
+        hero.dead = true;
+      }
+  }
+  //updateEnemies();
+	// Are they touching?
+};
+
+var collision = function(shot, enemy){
+  return shot.x <= (enemy.x + 32)
+		&& enemy.x <= (shot.x + 32)
+		&& shot.y <= (enemy.y + 32)
+		&& enemy.y <= (shot.y + 32)
+}
+
+//AI METHODS
+setInterval(function(){updateEnemies()}, 500);
+
+setInterval(function(){enemyShot()}, 1000);