docs: function getLocalServerConfig(configOpts = {}, opts = {}) {
      // 注意要用 _.merge，因为 Object.assign 会将 undefined 属性值也拷贝过去
      let localServerConfig = new LocalServerConfig(_.merge({}, configOpts, opts));
  
      if (!localServerConfig.isValid()) {
          return null;
      }
  
      return localServerConfig;
  }