Validatorjs

Validatorjs is a JavaScript library for validating data. It provides a concise interface that lets developers declare validation rules for individual fields in a data object. The library is designed to run in both Node.js and browser environments and is commonly used to verify user input before processing or storage.

Validation is defined by pairing a data object with a rules object, where each field maps to a string describing the validators to apply. Rules can cover common checks such as required fields, type checks (email, URL, numeric), length constraints, and format validations. Validatorjs evaluates the data against the rules and reports whether the input passes validation and, if not, returns a collection of error messages.

Customization: It supports customizing error messages and extending the validator set with custom rules. This makes it adaptable to domain-specific requirements. The library emphasizes a lightweight footprint and a straightforward API, making it suitable for form validation, API input validation, and similar tasks.

See also: It is an open-source project with community contributions and is typically installed via npm. Usage generally involves importing the library, creating a validation instance with data and rules, and inspecting the result or accessing the errors for user feedback.