---

name: using-typescript-types description: >- Guides TypeScript type usage: type vs interface decision, avoiding any, and Zod runtime validation. Use when defining types, choosing type patterns, or validating external data. Triggers: "type vs interface", "any", "unknown", "Zod", "运行时验证", "类型".

TypeScript 类型规范

核心约定

Type vs Interface

Copy默认用 type
│
├─ 需要声明合并（扩展第三方库）→ interface
├─ 类的契约（implements）→ interface
└─ 其他情况 → type

禁止 any

Copy// ✗ any
function process(data: any) { }

// ✓ unknown + 类型守卫
function process(data: unknown) {
  if (typeof data === 'string') {
    console.log(data.toUpperCase())
  }
}

// 类型谓词
function isUser(v: unknown): v is User {
  return typeof v === 'object' && v !== null && 'id' in v
}

运行时验证 (Zod)

外部数据必须验证（API、表单、环境变量、配置文件）：

Copyimport { z } from 'zod'

const UserSchema = z.object({
  id: z.string(),
  name: z.string(),
  email: z.string().email(),
})

type User = z.infer<typeof UserSchema>

// 验证 API 响应
const user = UserSchema.parse(await res.json())

详细 Zod 模式参见 references/zod-patterns.md