如何在TypeScript中加载带枚举值的JSON并转换为对应类型对象

开发者阿泽

2026-9-28

解决方案

你当前使用的是默认数字枚举，JSON中的sport是字符串类型，无法直接和枚举类型兼容，需要做显式转换和校验，不能直接用as强转绕过类型检查。

方案1：保留现有数字枚举，做键值映射转换

import * as someObject from "./deleteme.json";

enum Sports {
  skiing,
  hiking,
}

interface Person {
  name: string;
  sport: Sports;
}

// 校验sport值是否为合法枚举键
if (!Object.keys(Sports).includes(someObject.sport)) {
  throw new Error(`非法运动类型: ${someObject.sport}`);
}

// 字符串转枚举值
const steve: Person = {
  ...someObject,
  sport: Sports[someObject.sport as keyof typeof Sports]
};

console.log(steve);

方案2：改用字符串枚举，转换逻辑更直观

如果你的枚举值需要和字符串直接对齐，可以将枚举定义为字符串枚举，后续适配更简单：

import * as someObject from "./deleteme.json";

enum Sports {
  skiing = "skiing",
  hiking = "hiking",
}

interface Person {
  name: string;
  sport: Sports;
}

// 自定义类型守卫校验值合法性
const isValidSport = (val: string): val is Sports => {
  return Object.values(Sports).includes(val as Sports);
};

if (!isValidSport(someObject.sport)) {
  throw new Error(`非法运动类型: ${someObject.sport}`);
}

const steve: Person = {
  ...someObject,
  sport: someObject.sport
};

console.log(steve);