The validatorjs library makes data validation in JavaScript very easy in both the browser and Node.js. This library was inspired by the Laravel framework's Validator.

• Not dependent on any libraries.
• Works in both the browser and Node.
• Readable and declarative validation rules.
• Error messages with multilingual support.
• AMD/Require.js and CommonJS/Browserify support.

Grab validatorjs from Bower, NPM, or the /dist directory on Github:

bower install validatorjs

npm install validatorjs

<script src="validator.min.js"></script>

var Validator = require('validatorjs');

var validation = new Validator(data, rules [, customErrorMessages]);

data {Object} - The data you want to validate

rules {Object} - Validation rules

customErrorMessages {Object} - Optional custom error messages to return

var data = {
	name: 'John',
	email: '[email protected]',
	age: 28
};

var rules = {
	name: 'required',
	email: 'required|email',
	age: 'min:18'
};

var validation = new Validator(data, rules);

validation.passes(); // true
validation.fails(); // false

To apply validation rules to the data object, use the same object key names for the rules object.

var validation = new Validator({
	name: 'D',
	email: 'not an email address.com'
}, {
	name: 'size:3',
	email: 'required|email'
});

validation.fails(); // true
validation.passes(); // false

// Error messages
validation.errors.first('email'); // 'The email format is invalid.'
validation.errors.get('email'); // returns an array of all email error messages

Nested objects can also be validated. There are two ways to declare validation rules for nested objects. The first way is to declare the validation rules with a corresponding nested object structure that reflects the data. The second way is to declare validation rules with flattened key names. For example, to validate the following data:

var data = {
  name: 'John',
  bio: {
    age: 28,
    education: {
      primary: 'Elementary School',
      secondary: 'Secondary School'
    }
  }
};

We could declare our validation rules as follows:

var nested = {
  name: 'required',
  bio: {
    age: 'min:18',
    education: {
      primary: 'string',
      secondary: 'string'
    }
  }
};

// OR

var flattened = {
  'name': 'required',
  'bio.age': 'min:18'
  'bio.education.primary': 'string',
  'bio.education.secondary': 'string'
};

Validation rules do not have an implicit 'required'. If a field is undefined or an empty string, it will pass validation. If you want a validation to fail for undefined or '', use the required rule.

The field under validation must be yes, on, 1 or true. This is useful for validating "Terms of Service" acceptance.

The field under validation must be entirely alphabetic characters.

The field under validation may have alpha-numeric characters, as well as dashes and underscores.

The field under validation must be entirely alpha-numeric characters.

The field under validation must be an array.

The field under validation must have a size between the given min and max. Strings, numerics, and files are evaluated in the same fashion as the size rule.

The field under validation must be a boolean value of the form true, false, 0, 1, 'true', 'false', '0', '1',

The field under validation must have a matching field of foo_confirmation. For example, if the field under validation is password, a matching password_confirmation field must be present in the input.

The field under validation must be a valid date format which is acceptable by Javascript's Date object.

The field under validation must be numeric and must have an exact length of value.

The given field must be different than the field under validation.

The field under validation must be formatted as an e-mail address.

The field under validation must be included in the given list of values. The field can be an array or string.

The field under validation must have an integer value.

Validate that an attribute is no greater than a given size

Note: Maximum checks are inclusive.

Validate that an attribute is at least a given size.

Note: Minimum checks are inclusive.

The field under validation must not be included in the given list of values.

Validate that an attribute is numeric. The string representation of a number will pass.

Checks if the length of the String representation of the value is >

The given field must match the field under validation.

The field under validation must have a size matching the given value. For string data, value corresponds to the number of characters. For numeric data, value corresponds to a given integer value.

The field under validation must be a string.

Validate that an attribute has a valid URL format

The field under validation must match the given regular expression.

Note: When using the regex pattern, it may be necessary to specify rules in an array instead of using pipe delimiters, especially if the regular expression contains a pipe character. For each backward slash that you used in your regex pattern, you must escape each one with another backward slash.

var validation = new Validator({
	name: 'Doe',
	salary: '10,000.00',
	yearOfBirth: '1980'
}, {
	name: 'required|size:3',
	salary: ['required', 'regex:/^(?!0\\.00)\\d{1,3}(,\\d{3})*(\\.\\d\\d)?$/'],
	yearOfBirth: ['required', 'regex:/^(19|20)[\\d]{2,2}$/']
});

validation.fails(); // false
validation.passes(); // true

Validator.register(name, callbackFn, errorMessage);

name {String} - The name of the rule.

callbackFn {Function} - Returns a boolean to represent a successful or failed validation.

errorMessage {String} - An optional string where you can specify a custom error message. :attribute inside errorMessage will be replaced with the attribute name.

Validator.register('telephone', function(value, requirement, attribute) { // requirement parameter defaults to null
	return value.match(/^\d{3}-\d{3}-\d{4}$/);
}, 'The :attribute phone number is not in the format XXX-XXX-XXXX.');

Register an asynchronous rule which accepts a passes callback:

Validator.registerAsync('username_available', function(username, attribute, req, passes) {
	// do your database/api checks here etc
	// then call the `passes` method where appropriate:
	passes(); // if username is available
	passes(false, 'Username has already been taken.'); // if username is not available
});

Then call your validator passing a callback to fails or passes like so:

var validator = new Validator({ username: 'test123' }, { username: 'required|min:3|username_available' });
validator.passes(function() {
	// Validation passed
});

// Or call fails()
validator.fails(function() {
	// Error message:
	validator.errors.first('username');
});

Note: if you attempt to call passes or fails without a callback and the validator detects there are asynchronous validation rules, an exception will be thrown.

This contructor will automatically generate error messages for validation rules that failed.

If there are errors, the Validator instance will have its errors property object populated with the error messages for all failing attributes. The methods and properties on the errors property object are:

returns the first error message for an attribute, false otherwise

returns an array of error messages for an attribute, or an empty array if there are no errors

returns an object containing all error messages for all failing attributes

returns true if error messages exist for an attribute, false otherwise

the number of validation errors

var validation = new Validator(input, rules);
validation.errors.first('email'); // returns first error message for email attribute
validator.errors.get('email'); // returns an array of error messages for the email attribute

If you need a specific error message and you don't want to override the default one, you can pass an override as the third argument to the Validator object, just like with Laravel.

var input = {
	name: ''
};

var rules = {
	name : 'required'
};

var validation = new Validator(input, rules, { required: 'You forgot to give a :attribute' });
validation.errors.first('name'); // returns 'You forgot to give a name'

Some of the validators have string and numeric versions. You can change them too.

var input = {
	username: 'myusernameistoolong'
};

var rules = {
	username : 'max:16'
};

var validation = new Validator(input, rules, {
	max: {
		string: 'The :attribute is too long. Max length is :max.'
	}
});

validation.errors.first('username'); // returns 'The username is too long. Max length is 16.'

You can even provide error messages on a per attribute basis! Just set the message's key to 'validator.attribute'

var input = { name: '', email: '' };
var rules = { name : 'required', email : 'required' };

var validation = new Validator(input, rules, {
	"required.email": "Without an :attribute we can't reach you!"
});

validation.errors.first('name'); // returns  'The name field is required.'
validation.errors.first('email'); // returns 'Without an email we can\'t reach you!'

To display a custom "friendly" attribute name in error messages, use .setAttributeNames()

var validator = new Validator({ name: '' }, { name: 'required' });
validator.setAttributeNames({ name: 'custom_name' });
if (validator.fails()) {
	validator.errors.first('name'); // "The custom_name field is required."
}

Alternatively you can supply global custom attribute names in your lang with the attributes property.

You can also configure a custom attribute formatter:

// Configure global formatter.
Validator.setAttributeFormatter(function(attribute) {
	return attribute.replace(/_/g, ' ');
});

// Or configure formatter for particular instance.
var validator = new Validator({ first_name: '' }, { first_name: 'required' });
validator.setAttributeFormatter(function(attribute) {
	return attribute.replace(/_/g, ' ');
});
if (validator.fails()) {
	console.log(validator.errors.first('first_name')); // The first name field is required.
}

Note: by default all _[] characters will be replaced with spaces.

Error messages are in English by default. To include another language in the browser, reference the language file in a script tag and call Validator.useLang('lang_code').

<script src="dist/validator.min.js"></script>
<script src="dist/lang/ru.js"></script>
<script>
	Validator.useLang('es');
</script>

In Node, it will automatically pickup on the language source files.

var Validator = require('validatorjs');
Validator.useLang('ru');

If you don't see support for your language, please add one to src/lang!

You can also add your own custom language by calling setMessages:

Validator.setMessages('lang_code', {
	required: 'The :attribute field is required.',
	....
	....
});

Get the raw object of messages for the given language:

Validator.getMessages('lang_code');

Switch the default language used by the validator:

Validator.useLang('lang_code');

Get the default language being used:

Validator.getDefaultLang(); // returns e.g. 'en'

Override default messages for language:

var messages = Validator.getMessages('en');
messages.required = 'Whoops, :attribute field is required.';
Validator.setMessages('en', messages);