Bump to v4.12.0.

_getMapData.js

@@ -0,0 +1,19 @@
+define(['./_isKeyable'], function(isKeyable) {
+
+  /**
+   * Gets the data for `map`.
+   *
+   * @private
+   * @param {Object} map The map to query.
+   * @param {string} key The reference key.
+   * @returns {*} Returns the map data.
+   */
+  function getMapData(map, key) {
+    var data = map.__data__;
+    return isKeyable(key)
+      ? data[typeof key == 'string' ? 'string' : 'hash']
+      : data.map;
+  }
+
+  return getMapData;
+});