--- /dev/null
+'use strict';
+
+module.exports = function () {
+ var isSafeInteger = Number.isSafeInteger;
+ if (typeof isSafeInteger !== 'function') return false;
+ return !isSafeInteger('23') && isSafeInteger(34232322323) &&
+ !isSafeInteger(9007199254740992);
+};