typescript

TypeScript code review for React projects requires explicit types on public APIs, forbids `any`, mandates `unknown` with narrowing, and enforces stable keys with complete hook dependency arrays to prevent unsafe implementations.

To validate inputs and handle secrets in a Next.js application, mandate Zod schemas for all external inputs and require secret values via `process.env` with startup fail-fast checks. This enforces safer development by turning missing security requirements into explicit specification constraints.

The best way to write safer TypeScript specifications is to turn missing requirements into explicit constraints covering type safety, React hook dependencies, Zod validation, security anti-patterns, and Playwright E2E coverage. This prevents fragile implementations by forcing precise documentation the code generator can follow.

This specification approach works with Svelte and JavaScript projects, not only TypeScript. It applies to projects spanning .ts/.tsx/.js/.jsx files, package.json/tsconfig.json configurations, and common UI stacks including React, Next.js, and Svelte for both new builds and code-spec reviews.

To set up Playwright E2E testing for critical flows in a TypeScript project, require Playwright with safe selectors for all critical user paths. This is enforced alongside a structured review checklist for security, type safety, async correctness, and Node.js pitfalls to ensure comprehensive coverage.