How Do You Validate `unknown` in TypeScript Without a Schema Library? 🛡️

说明与用途

在 TypeScript 中无需完整模式库即可验证 unknown：使用 is-kit 构建 guard，既能在运行时验证，又能让 TypeScript 进行类型收窄，避免不安全的类型断言。

问题

How to safely turn an unknown value from untrusted boundaries into a usable type without relying on a full schema library?

结果

Runtime guards from is-kit provide lightweight validation that both narrows TypeScript types and ensures runtime safety, eliminating the need for full schema libraries in simple boundary checks.

工作流

• Declare input as unknown
• Define a guard using is-kit predicates (e.g., isString, oneOfValues, struct)
• Use the guard in an if statement to narrow the type
• Optionally call safeParse to get a {valid, value} result
• Handle invalid cases (e.g., return 400)
• Render or use the validated value

证据

as User changes what the compiler believes. It does not inspect the runtime value.

来源

With is-kit, we can build a guard like this…

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safeParse gives us a small tagged result…

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