sorting keys in JSON

sortjsonkeys.js

var json = JSON.stringify(data, function(key, value) {
  if (value instanceof Object === false || Object.getPrototypeOf(value) !== Object.prototype) {
    return value;
  }
  var keys = Object.keys(value);
  keys.sort();
  var newValue = {};
  keys.forEach(function(key) {
    newValue[key] = value[key];
  });
  return newValue;
}, 2)