Request Validation

Validate Express request bodies using TypeScript type guards by applying runtime checks at API boundaries to enforce interfaces and reject invalid inputs early. This ensures strict compile-time and runtime type safety for server-side handlers before processing.

Return specific field-level errors for invalid API requests by validating data structures against defined interfaces and outputting clear messages like { error: 'Invalid month', field: 'month' }. This pinpoints exact validation failures for the client.

Enforce strict validation for RenderRequest data in an Express handler by checking fields like month (1-12), valid years, and the books array structure. This guarantees payload completeness before the server processes the video rendering request.

You can use TypeScript type guards for server-side video data validation to enforce business rules like frame counts, durations, and book data completeness. This rejects invalid video constraints early at the API boundary.

API validation should happen at the server boundary because this is a server-to-server API where client-side validation is bypassed. Validating input early at the Express handler ensures robust, production-grade type safety before any processing begins.

Validate RecapBook data structures against defined TypeScript interfaces by using type guards to check data completeness and enforce types from src/lib/types.ts. This guarantees the RecapBook payload matches API boundary requirements before processing.