typescript-best-practices

Prevent runtime errors in TypeScript by applying Zod schemas at trust boundaries to parse and validate API responses, converting external data into strongly typed domain models using safeParse for untrusted input.

Make illegal states unrepresentable by using discriminated unions, branded types, and const assertions to ensure only valid state combinations are possible at compile time.

Use Zod safeParse for external input validation at trust boundaries where data may be malformed, and use parse for internal data already guaranteed safe by TypeScript type definitions.

Enforce exhaustive switch checks in TypeScript by using never-based guards and discriminated unions, ensuring all possible cases are handled and simplifying complex types for maintainability.

Yes, these type-safe patterns apply to .ts, .tsx, .js files and tsconfig.json, guiding library development, API handlers, and React component code reviews for safer JavaScript and TypeScript codebases.

Infer TypeScript types from Zod schemas to establish a single source of truth, eliminating duplicate type definitions and ensuring runtime validation automatically stays synchronized with compile-time types.