From bacaaaef8a18cbc5264b31f63f03434ac16e3204 Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Tue, 6 Jun 2017 07:06:47 -0700
Subject: [PATCH] Support symbols in property paths of `set`. [closes #3189]

---
 .internal/isIndex.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/.internal/isIndex.js b/.internal/isIndex.js
index 3d9e218a2..f53a11f53 100644
--- a/.internal/isIndex.js
+++ b/.internal/isIndex.js
@@ -13,10 +13,13 @@ const reIsUint = /^(?:0|[1-9]\d*)$/
  * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
  */
 function isIndex(value, length) {
+  const type = typeof value
   length = length == null ? MAX_SAFE_INTEGER : length
+
   return !!length &&
-    (typeof value == 'number' || reIsUint.test(value)) &&
-    (value > -1 && value % 1 == 0 && value < length)
+    (type == 'number' ||
+      (type != 'symbol' && reIsUint.test(value))) &&
+        (value > -1 && value % 1 == 0 && value < length)
 }
 
 export default isIndex