diff --git a/lib/6to5/transformation/templates/sliced-to-array.js b/lib/6to5/transformation/templates/sliced-to-array.js
index af2f04e8e7..3ef086127c 100644
--- a/lib/6to5/transformation/templates/sliced-to-array.js
+++ b/lib/6to5/transformation/templates/sliced-to-array.js
@@ -1,14 +1,14 @@
 (function (arr, i) {
-  if (!arr || !arr[Symbol.iterator]) {
-    throw new TypeError("Invalid attempt to destructure non-iterable instance");
-  } else if (Array.isArray(arr)) {
+  if (Array.isArray(arr)) {
     return arr;
-  } else {
+  } else if (Symbol.iterator in arr) {
     var _arr = [];
     for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
       _arr.push(_step.value);
       if (i && _arr.length === i) break;
     }
     return _arr;
+  } else {
+    throw new TypeError("Invalid attempt to destructure non-iterable instance");
   }
 });