Bump to v4.1.0.

_MapCache.js

@@ -0,0 +1,31 @@
+var mapClear = require('./_mapClear'),
+    mapDelete = require('./_mapDelete'),
+    mapGet = require('./_mapGet'),
+    mapHas = require('./_mapHas'),
+    mapSet = require('./_mapSet');
+
+/**
+ * Creates a map cache object to store key-value pairs.
+ *
+ * @private
+ * @param {Array} [values] The values to cache.
+ */
+function MapCache(values) {
+  var index = -1,
+      length = values ? values.length : 0;
+
+  this.clear();
+  while (++index < length) {
+    var entry = values[index];
+    this.set(entry[0], entry[1]);
+  }
+}
+
+// Add functions to the `MapCache`.
+MapCache.prototype.clear = mapClear;
+MapCache.prototype['delete'] = mapDelete;
+MapCache.prototype.get = mapGet;
+MapCache.prototype.has = mapHas;
+MapCache.prototype.set = mapSet;
+
+module.exports = MapCache;