validate.js

What is validate.js?

Validate.js is a lightweight JavaScript library for data validation. It provides a simple and flexible way to validate data structures, ensuring that they meet specified criteria. The library supports a wide range of validation rules and can be easily extended to include custom validations.

What are validate.js's main functionalities?

Basic Validation

This feature allows you to validate basic data structures against a set of predefined constraints. In this example, the 'name' field must be present and have a minimum length of 3 characters, and the 'email' field must be present and follow a valid email format.

const validate = require('validate.js');

const constraints = {
  name: {
    presence: true,
    length: {
      minimum: 3
    }
  },
  email: {
    presence: true,
    email: true
  }
};

const data = {
  name: 'John Doe',
  email: '[e-mail]'
};

const validationResult = validate(data, constraints);
console.log(validationResult);

Custom Validation

This feature allows you to define custom validation rules. In this example, a custom validator is created to check if the 'customField' matches the expected value. If it doesn't, a custom error message is returned.

const validate = require('validate.js');

validate.validators.customValidator = function(value, options, key, attributes) {
  if (value !== options.expectedValue) {
    return options.message || `${key} is not valid`;
  }
};

const constraints = {
  customField: {
    customValidator: {
      expectedValue: 'expectedValue',
      message: 'Custom validation failed'
    }
  }
};

const data = {
  customField: 'wrongValue'
};

const validationResult = validate(data, constraints);
console.log(validationResult);

Asynchronous Validation

This feature supports asynchronous validation, which is useful for scenarios where validation depends on external data or processes. In this example, an asynchronous validator checks if the 'asyncField' matches the expected value after a delay.

const validate = require('validate.js');

validate.validators.asyncValidator = function(value, options, key, attributes) {
  return new validate.Promise(function(resolve, reject) {
    setTimeout(function() {
      if (value !== options.expectedValue) {
        resolve(options.message || `${key} is not valid`);
      } else {
        resolve();
      }
    }, 1000);
  });
};

const constraints = {
  asyncField: {
    asyncValidator: {
      expectedValue: 'expectedValue',
      message: 'Asynchronous validation failed'
    }
  }
};

const data = {
  asyncField: 'wrongValue'
};

validate.async(data, constraints).then(function(validationResult) {
  console.log(validationResult);
});

Other packages similar to validate.js

joi

Joi is a powerful schema description language and data validator for JavaScript. It allows you to create blueprints or schemas for JavaScript objects to ensure validation of key information. Compared to Validate.js, Joi offers a more extensive and expressive API for defining complex validation rules and is widely used in Node.js applications.

yup

Yup is a JavaScript schema builder for value parsing and validation. It is similar to Joi but is often preferred for its simplicity and ease of use, especially in React applications. Yup provides a fluent API for object schema validation and integrates well with form libraries like Formik.

validator

Validator is a library of string validators and sanitizers. It is less comprehensive than Validate.js, focusing primarily on string validation and sanitization. It is lightweight and easy to use for common validation tasks such as checking email formats, URLs, and other string-based validations.

README

validate.js

Validate.js provides a declarative way of validating javascript objects.

For documentation please see validatejs.org/.

For issues and feature requests visit the issue tracker.

Build status

Contributing

Before opening a pull request please make sure your changes follow the contribution guidelines.