Your Type Guard Can Silently Drift from Your TypeScript Type 🔧

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TypeScript type guard drift, practical and technically detailed.

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Why It Matters

For a solutions architect focused on developer experience and type safety, this addresses a common source of runtime bugs in TypeScript codebases that rely on custom type guards.

Key Takeaways

Use typedStruct from is-kit to enforce compile-time alignment between type guards and their corresponding types.

Your Type Guard Can Silently Drift from Your TypeScript Type 🔧

Summary

TypeScript's user-defined type predicates (e.g., `value is User`) can silently drift from the actual type when fields are added or changed, because the compiler trusts the developer's runtime logic. The `is-kit` library's `typedStruct` function solves this by tying the guard definition to the type structure via a type-level relationship, making mismatches visible at compile time.

Author

nyaomaru