TypeScript中为CountersData接口赋值属性的更高效方法？

当前给CountersData接口属性赋值的实现逻辑如下：

• 调用flattenObject工具方法，从responseDeploymentData中提取最深层级的键值数据，得到扁平化对象
• 逐行手动将扁平化对象中对应字段赋值给CountersData类型的实例

这种逐行赋值的写法冗余度较高，需要更高效简洁的实现方式。

原有代码实现 #

interface CountersData {
  //more properties

  count_targets?: number;
  count_targets_excluded?: number;
  count_targets_pending?: number;
  count_targets_in_progress?: number;
  count_targets_completed?: number;
  count_targets_failed?: number;
}
// 后续业务代码
  const countersData = {} as CountersData;
  let targetData: any = flattenObject(responseDeploymentData);
  countersData.count_targets = targetData.count_targets;
  countersData.count_targets_excluded = targetData.count_targets_excluded;
  countersData.count_targets_pending = targetData.count_targets_pending;
  countersData.count_targets_in_progress = targetData.count_targets_in_progress;
  countersData.count_targets_completed = targetData.count_targets_completed;
  countersData.count_targets_failed = targetData.count_targets_failed;

已尝试的方案 #

['count_targets', 'count_targets_excluded'].forEach(key => countersData[key] = targetData[key]);

你尝试的forEach遍历赋值思路是可行的，核心优化方向是补全类型约束+抽离通用逻辑，避免重复代码同时保证类型安全，下面是两种常用的实现方式，按需选择即可：

方案1：通用字段提取方法（推荐） #

抽一个可复用的pick工具方法，后续其他需要从大对象里挑同名字段的场景都能直接用，TS会自动做类型校验，要是不小心拼错字段名，编译阶段就会报错，不用等到运行时踩坑：

/**
 * 从源对象中提取指定键对应的字段，返回目标结构对象
 */
function pick<T, K extends keyof T>(source: Partial<T>, keys: K[]): Pick<T, K> {
  return keys.reduce((result, key) => {
    result[key] = source[key];
    return result;
  }, {} as Pick<T, K>);
}

// 业务代码使用
const targetData = flattenObject(responseDeploymentData);
// 定义需要提取的字段列表，类型约束为CountersData的键名集合
const counterFieldKeys: (keyof CountersData)[] = [
  'count_targets',
  'count_targets_excluded',
  'count_targets_pending',
  'count_targets_in_progress',
  'count_targets_completed',
  'count_targets_failed'
];
const countersData: CountersData = pick(targetData, counterFieldKeys);

后续如果CountersData接口新增同名字段，只要在counterFieldKeys数组里新增对应字段名即可，不需要重复写赋值语句。

方案2：直接解构赋值（适合字段少、无复用需求的场景） #

如果不需要复用逻辑，也可以直接在对象初始化时解构赋值，比逐行赋值更紧凑，也能通过TS类型校验：

const targetData = flattenObject(responseDeploymentData);
const countersData: CountersData = {
  count_targets: targetData.count_targets,
  count_targets_excluded: targetData.count_targets_excluded,
  count_targets_pending: targetData.count_targets_pending,
  count_targets_in_progress: targetData.count_targets_in_progress,
  count_targets_completed: targetData.count_targets_completed,
  count_targets_failed: targetData.count_targets_failed
};

注意事项 #

别直接用扩展运算符{...targetData}给countersData赋值，flattenObject拍平对象后会带出很多嵌套层级的字段，大部分和CountersData没关系，直接展开会把多余属性混进目标对象，容易引发后续逻辑bug。

内容的提问来源于stack exchange，提问作者user19251203