Bump to v4.1.0.

_cachePush.js

@@ -0,0 +1,27 @@
+import isKeyable from './_isKeyable';
+
+/** Used to stand-in for `undefined` hash values. */
+var HASH_UNDEFINED = '__lodash_hash_undefined__';
+
+/**
+ * Adds `value` to the set cache.
+ *
+ * @private
+ * @name push
+ * @memberOf SetCache
+ * @param {*} value The value to cache.
+ */
+function cachePush(value) {
+  var map = this.__data__;
+  if (isKeyable(value)) {
+    var data = map.__data__,
+        hash = typeof value == 'string' ? data.string : data.hash;
+
+    hash[value] = HASH_UNDEFINED;
+  }
+  else {
+    map.set(value, HASH_UNDEFINED);
+  }
+}
+
+export default cachePush;