diff --git a/lib/6to5/transformation/transformers/es6-computed-property-names.js b/lib/6to5/transformation/transformers/es6-computed-property-names.js
index bc3c9091f2..f84a522086 100644
--- a/lib/6to5/transformation/transformers/es6-computed-property-names.js
+++ b/lib/6to5/transformation/transformers/es6-computed-property-names.js
@@ -60,10 +60,10 @@ var spec = function (node, body, objId, initProps, file) {
   // normalise key
 
   for (var i in props) {
-    prop = props[i];
+    var prop = props[i];
     if (prop.kind !== "init") continue;
 
-    key = prop.key;
+    var key = prop.key;
 
     if (!prop.computed && t.isIdentifier(key)) {
       prop.key = t.literal(key.name);