Use a regular Map in the walk function

Author: skerit

lib/json-dry.js

@@ -1470,7 +1470,7 @@ function stringify(value, replacer, space) {
  *
  * @author   Jelle De Loecker   <jelle@elevenways.be>
  * @since    0.4.2
- * @version  1.0.0
+ * @version  2.0.1
  *
  * @param    {Object}     obj     The object to walk over
  * @param    {Function}   fnc     The function to perform on every entry
@@ -1487,7 +1487,7 @@ function walk(obj, fnc, result, seen) {
 	    i;
 
 	if (!seen) {
-		seen = new WeakMap();
+		seen = new Map();
 	}
 
 	seen.set(obj, true);