-    const panLeft = () => {
+    const panLeft = (() => {
       const v = new Vector3();

-      return function panLeft(distance, objectMatrix) {
+      return (distance, objectMatrix) => {
         v.setFromMatrixColumn(objectMatrix, 0); // get X column of objectMatrix
         v.multiplyScalar(-distance);

         panOffset.add(v);

       };
-    };
+    })();