Validation Interview Questions

React forms work through controlled inputs where state is the single source of truth. Understand the cycle, real-time validation, input formatting, and the multi-field pattern with a shared handler.

PropTypes validate prop types and required props at runtime in development, logging console warnings on violations. In TypeScript projects, PropTypes are superseded by interface declarations and compile-time checking. Know what each serves: PropTypes = runtime dev warnings, TypeScript = compile-time safety.

Learn to build a dynamic form builder in React that renders form fields based on JSON schema, supports validation, conditional logic, and reusable components.