Class Validator
Class Validator is a TypeScript and JavaScript library that uses decorators to validate class properties based on metadata. It allows developers to define validation rules directly in their class definitions, making it easy to ensure data integrity for objects like DTOs (Data Transfer Objects) or entities. The library supports a wide range of validators, such as checking for required fields, string lengths, email formats, and custom validation logic.
Developers should use Class Validator when building applications in TypeScript or JavaScript that require robust input validation, especially in backend services, APIs, or form handling. It is particularly useful in frameworks like NestJS, where it integrates seamlessly for validating incoming request data, helping to prevent errors and security vulnerabilities by ensuring data meets specified criteria before processing.