1 files changed, 23 insertions, 0 deletions
diff --git a/lib/internal/keyIterator.js b/lib/internal/keyIterator.js
new file mode 100644
index 0000000..0e2b0c3
--- /dev/null
+++ b/lib/internal/keyIterator.js
@@ -0,0 +1,23 @@
+'use strict';
+
+import isArrayLike from 'lodash/isArrayLike';
+import keys from 'lodash/keys';
+
+export default function keyIterator(coll) {
+    var i = -1;
+    var len;
+    if (isArrayLike(coll)) {
+        len = coll.length;
+        return function next() {
+            i++;
+            return i < len ? i : null;
+        };
+    } else {
+        var okeys = keys(coll);
+        len = okeys.length;
+        return function next() {
+            i++;
+            return i < len ? okeys[i] : null;
+        };
+    }
+}