ts-best-practices

该 Skill 汇总 TypeScript 类型安全准则，涵盖避免 as 断言、用 unknown 替代 any、判别联合、类型收窄、类型守卫、穷尽检查和用 satisfies 保留字面量类型，并引导查看 references/patterns.md 中的示例。

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最近更新 2026-10-19 06:44:43

分类：开发依赖：纯提示词应用场景：代码审查 / 代码生成

安装技能

复制下面的话术发给你的 Agent，它会通过 secure-skills 检索并安装该技能。

执行命令安装此 skill： npx secure-skills-cli add poteto/noodle/ts-best-practices

Metadata

name: ts-best-practices
description: TypeScript type safety guidelines for writing maximally type-safe code. Apply these patterns when writing or reviewing any TypeScript: discriminated unions, type narrowing, type guards, exhaustiveness checks, avoiding `as` casts, preferring `unknown` over `any`, and making impossible states unrepresentable. Use this skill whenever writing TypeScript code, reviewing TypeScript for type safety issues, or when the user mentions type safety, type narrowing, discriminated unions, or asks to make types stricter/more explicit.

This project's TypeScript policy. Apply when writing or reviewing TypeScript.

Rule	Summary
No `as` casts	Every `as` is a potential runtime crash. Validate at boundaries, then cast only if earned. Prefer Zod/Valibot over manual validation.
`unknown` over `any`	`any` disables type checking for everything it touches. External data is always `unknown`.
Discriminated unions	Model variants with a shared literal discriminant. No optional-field bags.
Narrowing hierarchy	Prefer: discriminated union switch > `in` operator > typeof/instanceof > type guard > `as`
Type guards	Must actually verify the claim. Name them `isX` or `hasX`. Prefer discriminant narrowing when possible.
Exhaustiveness checks	Always add `default: never` arm to switches over discriminated unions. Use an `absurd()` helper to reduce boilerplate.
`satisfies` over `as`	When verifying a value matches a type without widening, use `satisfies` to preserve literal types.
Impossible states	If a bug requires asking "can this combination happen?" the type is too loose. Tighten it.

Read references/patterns.md for code examples of each rule.