--- /dev/null
+'use strict';
+
+var getPrototypeOf = Object.getPrototypeOf, prototype = Object.prototype
+ , toString = prototype.toString
+
+ , id = Object().toString();
+
+module.exports = function (value) {
+ var proto, constructor;
+ if (!value || (typeof value !== 'object') || (toString.call(value) !== id)) {
+ return false;
+ }
+ proto = getPrototypeOf(value);
+ if (proto === null) {
+ constructor = value.constructor;
+ if (typeof constructor !== 'function') return true;
+ return (constructor.prototype !== value);
+ }
+ return (proto === prototype) || (getPrototypeOf(proto) === null);
+};