Spieler kann nicht aus die gelbe Box laufen

js/allg.js

@@ -1,6 +1,8 @@
+// animation
 let playerAnim = [];
 let tomAnim = [];
 let enemyAnim = [];
+//player
 let playerAnimState = 0;
 let runDirection = 0;
 let runSpeed = 12;
@@ -11,6 +13,9 @@ let playerSprite = document.querySelector("#fuchs img");
 let dIsPressed = false;
 let aIsPressed = false;
 let runAnimation;
+// Map
+const boxBorderLeft = -40;
+const boxBorderRight = 840;
 
 fillArrays();
 startAnimation();
@@ -96,7 +101,11 @@ document.addEventListener('keyup', function(event)
 //---------------------------------------------------------- Move Player ------------------------------------------------------------
 function move()
 {
-    currentPosition = currentPosition + runDirection * runSpeed;
+    let nextPosition = currentPosition + runDirection * runSpeed;
+    if(nextPosition > boxBorderLeft && nextPosition < boxBorderRight)
+    {
+        currentPosition = nextPosition;
+    }
     player.style.left =  currentPosition + "px";
 }