diff --git a/tslib.es6.js b/tslib.es6.js
index 6da273e..6a9aced 100644
--- a/tslib.es6.js
+++ b/tslib.es6.js
@@ -43,8 +43,10 @@ export function __rest(s, e) {
     for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
         t[p] = s[p];
     if (s != null && typeof Object.getOwnPropertySymbols === "function")
-        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
-            t[p[i]] = s[p[i]];
+        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) {
+            if (e.indexOf(p[i]) < 0 && Object.prototype.propertyIsEnumerable.call(s, p[i]))
+                t[p[i]] = s[p[i]];
+        }
     return t;
 }
 
diff --git a/tslib.js b/tslib.js
index b0b1ff3..639fbcd 100644
--- a/tslib.js
+++ b/tslib.js
@@ -79,8 +79,10 @@ var __importDefault;
         for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
             t[p] = s[p];
         if (s != null && typeof Object.getOwnPropertySymbols === "function")
-            for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
-                t[p[i]] = s[p[i]];
+            for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) {
+                if (e.indexOf(p[i]) < 0 && Object.prototype.propertyIsEnumerable.call(s, p[i]))
+                    t[p[i]] = s[p[i]];
+            }
         return t;
     };