Coding Standards

Use these standards while designing and editing TypeScript. They encode the user's taste: correctness first, precise domain modeling, typed failures, deep modules, explicit boundaries, real-seam tests, strict TypeScript, and boring operational safety.

This skill is standalone. Load the topic files that match the code you are touching; do not treat the top-level summary as the whole standard.

Core tenets

• Correctness, safety, debuggability, boundary integrity, and test integrity come before convenience.
• Local conventions matter when they are compatible with these standards.
• Parse boundary input before it reaches core logic; pass refined/domain values inward.
• Model invariants in types, constructors, parsers, and transitions.
• Model expected failures in typed channels; reserve throws for defects and boundary translation.
• Design deep modules with intentional seams, small interfaces, and explicit dependencies.
• Verify observable behavior through real seams.
• Keep TypeScript contracts strict, local, documented, and boring.
• Improve changed paths without forcing broad migrations unless explicitly requested.
• Do not design for backwards compatibility, migrations, rollout, backfill, dual-write/read paths, or deployment sequencing unless the user explicitly asks. Treat new designs as the desired target state, not a migration plan.