Izmjenjena struktura, dodan backand

web/node_modules/core-js/modules/$.classof.js

@@ -0,0 +1,16 @@
+// getting tag from 19.1.3.6 Object.prototype.toString()
+var cof = require('./$.cof')
+  , TAG = require('./$.wks')('toStringTag')
+  // ES3 wrong here
+  , ARG = cof(function(){ return arguments; }()) == 'Arguments';
+
+module.exports = function(it){
+  var O, T, B;
+  return it === undefined ? 'Undefined' : it === null ? 'Null'
+    // @@toStringTag case
+    : typeof (T = (O = Object(it))[TAG]) == 'string' ? T
+    // builtinTag case
+    : ARG ? cof(O)
+    // ES3 arguments fallback
+    : (B = cof(O)) == 'Object' && typeof O.callee == 'function' ? 'Arguments' : B;
+};