sstur

function clone(obj) {
  if (Object(obj) !== obj) return obj;
  if (typeof obj.toJSON == 'function') {
    return obj.toJSON();
  }
  var type = toString.call(obj).slice(8, -1);
  if (type in CLONE) {
    return CLONE[type].call(obj, clone);
  }
  var copy = {};