如何重命名object的key？

function renameObjectKey(obj, oldKey, newKey) {
  if (obj.hasOwnProperty(oldKey)) {
    obj[newKey] = obj[oldKey];
    delete obj[oldKey];
  }
}

function renameObjectKeys(obj, keyMap) {
  var newObj = {};
  for (var key in obj) {
    if (obj.hasOwnProperty(key)) {
      if (keyMap.hasOwnProperty(key)) {
        renameObjectKey(obj, key, keyMap[key]);
      }
      newObj[key] = obj[key];
    }
  }
  return newObj;
}

// 示例用法
var obj = {
  name: 'John',
  age: 30,
  city: 'New York'
};

var keyMap = {
  name: 'fullName',
  age: 'newAge'
};

var renamedObj = renameObjectKeys(obj, keyMap);
console.log(renamedObj);