Bump to v4.12.0.

_mapCacheHas.js

@@ -0,0 +1,17 @@
+define(['./_getMapData'], function(getMapData) {
+
+  /**
+   * Checks if a map value for `key` exists.
+   *
+   * @private
+   * @name has
+   * @memberOf MapCache
+   * @param {string} key The key of the entry to check.
+   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+   */
+  function mapCacheHas(key) {
+    return getMapData(this, key).has(key);
+  }
+
+  return mapCacheHas;
+});