Bump to v4.3.0.

isMap.js

@@ -0,0 +1,27 @@
+define(['./_getTag', './isObjectLike'], function(getTag, isObjectLike) {
+
+  /** `Object#toString` result references. */
+  var mapTag = '[object Map]';
+
+  /**
+   * Checks if `value` is classified as a `Map` object.
+   *
+   * @static
+   * @memberOf _
+   * @category Lang
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+   * @example
+   *
+   * _.isMap(new Map);
+   * // => true
+   *
+   * _.isMap(new WeakMap);
+   * // => false
+   */
+  function isMap(value) {
+    return isObjectLike(value) && getTag(value) == mapTag;
+  }
+
+  return isMap;
+});