What problem does it solve? JavaScript and TypeScript codebases drift into inconsistent module styles, unsafe async patterns, swallowed errors, and injection-prone code when every contributor follows different habits. This Skill provides a single enforceable rulebook covering modules, naming, async correctness, errors, types, immutability, security, Node specifics, and tests. ## Core Features & Use Cases - Non-negotiable rules: Blocks var, loose equality, floating promises, empty catch blocks, eval, hardcoded secrets, and unjustified any types. - Ten rule sections: Covers ESM module structure, naming conventions, function design, async concurrency with Promise.all, error handling with cause, strict TypeScript typing, immutability, injection prevention, Node.js specifics, and deterministic testing. - Review checklist: Supplies a ready-made checklist for reviewing JavaScript diffs, including boundary validation, concurrency correctness, and lint/typecheck/test gates. - Use Case: When asked to refactor a Node.js API handler, the Skill ensures inputs are validated at the boundary, promises run concurrently with Promise.all, errors are rethrown with cause, and no secrets or SQL string concatenation slip in. ## Quick Start Review this TypeScript file against the JavaScript standards and list every rule violation with a suggested fix.
