Apply let/const transform.

_arrayEvery.js

@@ -9,8 +9,8 @@
  *  else `false`.
  */
 function arrayEvery(array, predicate) {
-  var index = -1,
-      length = array == null ? 0 : array.length;
+  let index = -1;
+  const length = array == null ? 0 : array.length;
 
   while (++index < length) {
     if (!predicate(array[index], index, array)) {