Functional TypeScript Code Review

Review server-side TypeScript code against the functional domain modeling principles defined in the functional-ts skill. This review uses the same knowledge base as functional-ts — every checklist item below corresponds to a section of that skill, and links to the authoritative description there.

Review Procedure

1. Load the principle knowledge first. Before reading any code under review, read the following so that findings cite the canonical principle:
   • ../functional-ts/SKILL.md — the principle index
   • ../functional-ts/error-handling.md
   • ../functional-ts/boundary-defense.md
   • ../functional-ts/state-modeling.md
   • The validation library guide matching the project's package.json under ../functional-ts/validation-libraries/ (zod.md / valibot.md / arktype.md)
   • The Result library guide matching the project's package.json under ../functional-ts/result-libraries/ (neverthrow.md / byethrow.md / fp-ts.md / option-t.md)
2. Read the files under review.
3. Walk through the checklist below in the order of the principles. The numbering mirrors functional-ts/SKILL.md.
4. When a violation is found, report it with the relevant principle, the reason it matters, and a fix.
5. When something is not a violation but has room for improvement, communicate it as a suggestion.

Checklist