ts-best-practices

as bypasses the compiler. Every as is a potential runtime crash the compiler can't catch.

The one exception: a cast immediately following exhaustive validation (as above) is acceptable because the cast is earned. But prefer a type guard or schema library (Zod, Valibot) over manual validation.

Refactoring as out of existing code: When encountering an as cast, determine why TypeScript can't infer the type. Usually one of:

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. Source: poteto/noodle.