To help you get started, we've collected the most common ways that validatorjs is being used within popular public projects.

validatorjs

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.

Why use validatorjs?

• Works in both the browser and Node.
• Readable and declarative validation rules.
• Error messages with multilingual support.
• CommonJS/Browserify support.
• ES6 support.

Installation

Using npm

npm install validatorjs

Using yarn

yarn add validatorjs

Browser

Node.js / Browserify

// ES5
let Validator = require('validatorjs');

// ES6
import * as Validator from 'validatorjs';

Basic Usage

let 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

Example 1 - Passing Validation

let data = {
  name: 'John',
  email: 'johndoe@gmail.com',
  age: 28
};

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

let 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.

Example 2 - Failing Validation

let 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 Rules

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:

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

We could declare our validation rules as follows:

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

// OR

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

WildCards Rules

WildCards can also be validated.

let data = {
  users: [{
    name: 'John',
    bio: {
      age: 28,
      education: {
        primary: 'Elementary School',
        secondary: 'Secondary School'
      }
    }
  }]
};

We could declare our validation rules as follows:

let rules = {
  'users.*.name': 'required',
  'users.*.bio.age': 'min:18',
  'users.*.bio.education.primary': 'string',
  'users.*.bio.education.secondary': 'string'
};

Available Rules

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.

accepted

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

after:date

The field under validation must be after the given date.

after_or_equal:date

The field unter validation must be after or equal to the given field

alpha

The field under validation must be entirely alphabetic characters.

alpha_dash

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

alpha_num

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

array

The field under validation must be an array.

before:date

The field under validation must be before the given date.

before_or_equal:date

The field under validation must be before or equal to the given date.

between:min,max

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.

boolean

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

confirmed

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.

date

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

digits:value

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

digits_between:min,max

The field under validation must be numeric and must have length between given min and max.

different:attribute

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

email

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

hex

The field under validation should be a hexadecimal format. Useful in combination with other rules, like hex|size:6 for hex color code validation.

in:foo,bar,...

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

integer

The field under validation must have an integer value.

max:value

Validate that an attribute is no greater than a given size

Note: Maximum checks are inclusive.

min:value

Validate that an attribute is at least a given size.

Note: Minimum checks are inclusive.

not_in:foo,bar,...

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

numeric

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

present

The field under validation must be present in the input data but can be empty.

required

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

required_if:anotherfield,value

The field under validation must be present and not empty if the anotherfield field is equal to any value.

required_unless:anotherfield,value

The field under validation must be present and not empty unless the anotherfield field is equal to any value.

required_with:foo,bar,...

The field under validation must be present and not empty only if any of the other specified fields are present.

required_with_all:foo,bar,...

The field under validation must be present and not empty only if all of the other specified fields are present.

required_without:foo,bar,...

The field under validation must be present and not empty only when any of the other specified fields are not present.

required_without_all:foo,bar,...

The field under validation must be present and not empty only when all of the other specified fields are not present.

same:attribute

The given field must match the field under validation.

size:value

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.

string

The field under validation must be a string.

url

Validate that an attribute has a valid URL format

regex:pattern

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.

Example 3 - Regex validation

let 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

Example 4 - Type Checking Validation

let validation = new Validator({
  age: 30,
  name: ''
}, {
  age: ['required', { 'in': [29, 30] }],
  name: [{ required_if: ['age', 30] }]
});

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

Register Custom Validation Rules

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.');

Asynchronous Validation

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 using checkAsync passing fails and passes callbacks like so:

let validator = new Validator({
	username: 'test123'
}, {
	username: 'required|min:3|username_available'
});

function passes() {
  // Validation passed
}

function fails() {
  validator.errors.first('username');
}

validator.checkAsync(passes, fails);

Error Messages

This constructor 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:

.first(attribute)

returns the first error message for an attribute, false otherwise

.get(attribute)

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

.all()

returns an object containing all error messages for all failing attributes

.has(attribute)

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

.errorCount

the number of validation errors

let 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

Custom Error Messages

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.

let input = {
  name: ''
};

let rules = {
  name : 'required'
};

let validation = new Validator(input, rules, { required: 'You forgot to give a :attribute' });
validation.passes();
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.

let input = {
  username: 'myusernameistoolong'
};

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

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

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

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

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

Custom Attribute Names

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

let 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.
let 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.

Language Support

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').

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

let 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:

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

License

Copyright © 2012-2019 David Tang Released under the MIT license

Credits

validatorjs created by David Tang validatorjs maintained by Mike Erickson and Contributors

E-Mail: codedungeon@gmail.com

Twitter: @codedungeon

Website: codedungeon.io