What is joi?

Joi is a validation library for JavaScript that aims to make input validation easy and intuitive. It allows you to define a schema for validating data structures and provides a rich set of validation rules and options. The library is widely used in Node.js applications and is often paired with frameworks like Hapi.js for server-side validation.

Some key features of Joi include:

  1. Schema-based validation: Joi allows you to define a schema that describes the shape and constraints of the data you want to validate.

  2. Rich set of validation rules: Joi provides a wide range of validation rules for different data types, such as strings, numbers, arrays, objects, and more. You can also write custom validation rules if needed.

  3. Chaining and composition: Joi allows you to chain multiple validation rules together and compose complex schemas from smaller pieces.

  4. Error handling: Joi provides detailed error messages when validation fails, making it easy to pinpoint the exact issues in the input data.

  5. Extensible: Joi is highly configurable and extensible, allowing you to tailor validation rules and behaviors to your specific needs.

Overall, Joi is a powerful and flexible tool for data validation in JavaScript applications, helping developers ensure that their input data meets the required criteria.