validator

What is validator?

The validator npm package is a library of string validators and sanitizers. It provides a variety of functions to validate and sanitize strings, such as checking if a string is in a certain format (e.g., email, URL) or transforming strings to ensure they are safe for use in different contexts.

What are validator's main functionalities?

Email Validation

Checks if the input string is an email.

const validator = require('validator');
console.log(validator.isEmail('[e-mail]')); // true

URL Validation

Checks if the input string is a URL.

const validator = require('validator');
console.log(validator.isURL('https://www.example.com')); // true

Sanitizing Strings

Escapes HTML characters in the input string to prevent XSS attacks.

const validator = require('validator');
console.log(validator.escape('<script>alert("xss")</script>')); // '&lt;script&gt;alert(&quot;xss&quot;)&lt;/script&gt;'

Checking String Length

Checks if the input string's length falls within a specified range.

const validator = require('validator');
console.log(validator.isLength('Hello', {min: 2, max: 10})); // true

Blacklisting Characters

Removes specified characters from the input string.

const validator = require('validator');
console.log(validator.blacklist('abc123', '123')); // 'abc'

Other packages similar to validator

joi

Joi is a powerful schema description language and data validator for JavaScript. It allows for a more detailed and structured validation process compared to validator, including the ability to create custom validation schemas.

yup

Yup is a JavaScript schema builder for value parsing and validation. It uses a schema-based approach similar to Joi and can be integrated with form libraries like Formik. It is more focused on object schema validation.

class-validator

Class-validator works with classes and decorators to validate that the properties of an object conform to specified rules. It is typically used with TypeScript and integrates well with class-based frameworks like TypeORM.

express-validator

Express-validator is a set of express.js middlewares that wraps validator.js functions. It is specifically designed for use with the Express web application framework and allows for easy integration of validation into the request processing pipeline.

README

validator.js

A library of string validators and sanitizers.

Server-side usage

Install the library with npm install validator

var validator = require('validator');

validator.isEmail('[e-mail]'); //=> true

ES6

import validator from 'validator';

Or, import only a subset of the library:

import { isEmail } from 'validator/lib/isEmail';

Client-side usage

The library can be loaded either as a standalone script, or through an AMD-compatible loader

<script type="text/javascript" src="validator.min.js"></script>
<script type="text/javascript">
  validator.isEmail('[e-mail]'); //=> true
</script>

The library can also be installed through bower

$ bower install validator-js

Strings only

This library validates and sanitizes strings only.

If you're not sure if your input is a string, coerce it using input + ''. Passing anything other than a string is an error.

Validators

• contains(str, seed) - check if the string contains the seed.
• equals(str, comparison) - check if the string matches the comparison.
• isAfter(str [, date]) - check if the string is a date that's after the specified date (defaults to now).
• isAlpha(str [, locale]) - check if the string contains only letters (a-zA-Z). Locale is one of ['ar', 'ar-AE', 'ar-BH', 'ar-DZ', 'ar-EG', 'ar-IQ', 'ar-JO', 'ar-KW', 'ar-LB', 'ar-LY', 'ar-MA', 'ar-QA', 'ar-QM', 'ar-SA', 'ar-SD', 'ar-SY', 'ar-TN', 'ar-YE', 'cs-CZ', 'de-DE', 'en-AU', 'en-GB', 'en-HK', 'en-IN', 'en-NZ', 'en-US', 'en-ZA', 'en-ZM', 'es-ES', 'fr-FR', 'hu-HU', 'nl-NL', 'pl-PL', 'pt-BR', 'pt-PT', 'ru-RU', 'sr-RS', 'sr-RS@latin', 'tr-TR']) and defaults to en-US.
• isAlphanumeric(str [, locale]) - check if the string contains only letters and numbers. Locale is one of ['ar', 'ar-AE', 'ar-BH', 'ar-DZ', 'ar-EG', 'ar-IQ', 'ar-JO', 'ar-KW', 'ar-LB', 'ar-LY', 'ar-MA', 'ar-QA', 'ar-QM', 'ar-SA', 'ar-SD', 'ar-SY', 'ar-TN', 'ar-YE', 'cs-CZ', 'de-DE', 'en-AU', 'en-GB', 'en-HK', 'en-IN', 'en-NZ', 'en-US', 'en-ZA', 'en-ZM', 'es-ES', 'fr-FR', 'fr-BE', 'hu-HU', 'nl-BE', 'nl-NL', 'pl-PL', 'pt-BR', 'pt-PT', 'ru-RU', 'sr-RS', 'sr-RS@latin', 'tr-TR']) and defaults to en-US.
• isAscii(str) - check if the string contains ASCII chars only.
• isBase64(str) - check if a string is base64 encoded.
• isBefore(str [, date]) - check if the string is a date that's before the specified date.
• isBoolean(str) - check if a string is a boolean.
• isByteLength(str, options) - check if the string's length (in bytes) falls in a range.options is an object which defaults to {min:0, max: undefined}.
• isCreditCard(str) - check if the string is a credit card.
• isCurrency(str, options) - check if the string is a valid currency amount. options is an object which defaults to {symbol: '$', require_symbol: false, allow_space_after_symbol: false, symbol_after_digits: false, allow_negatives: true, parens_for_negatives: false, negative_sign_before_digits: false, negative_sign_after_digits: false, allow_negative_sign_placeholder: false, thousands_separator: ',', decimal_separator: '.', allow_space_after_digits: false }.
• isDataURI(str) - check if the string is a data uri format.
• isDate(str) - check if the string is a date.
• isDecimal(str) - check if the string represents a decimal number, such as 0.1, .3, 1.1, 1.00003, 4.0, etc.
• isDivisibleBy(str, number) - check if the string is a number that's divisible by another.
• isEmail(str [, options]) - check if the string is an email. options is an object which defaults to { allow_display_name: false, allow_utf8_local_part: true, require_tld: true }. If allow_display_name is set to true, the validator will also match Display Name <email-address>. If allow_utf8_local_part is set to false, the validator will not allow any non-English UTF8 character in email address' local part. If require_tld is set to false, e-mail addresses without having TLD in their domain will also be matched.
• isFQDN(str [, options]) - check if the string is a fully qualified domain name (e.g. domain.com). options is an object which defaults to { require_tld: true, allow_underscores: false, allow_trailing_dot: false }.
• isFloat(str [, options]) - check if the string is a float. options is an object which can contain the keys min and/or max to validate the float is within boundaries (e.g. { min: 7.22, max: 9.55 }).
• isFullWidth(str) - check if the string contains any full-width chars.
• isHalfWidth(str) - check if the string contains any half-width chars.
• isHexColor(str) - check if the string is a hexadecimal color.
• isHexadecimal(str) - check if the string is a hexadecimal number.
• isIP(str [, version]) - check if the string is an IP (version 4 or 6).
• isISBN(str [, version]) - check if the string is an ISBN (version 10 or 13).
• isISIN(str) - check if the string is an ISIN (stock/security identifier).
• isISO8601(str) - check if the string is a valid ISO 8601 date.
• isIn(str, values) - check if the string is in a array of allowed values.
• isInt(str [, options]) - check if the string is an integer. options is an object which can contain the keys min and/or max to check the integer is within boundaries (e.g. { min: 10, max: 99 }). options can also contain the key allow_leading_zeroes, which when set to true will accept integer values with leading zeroes (e.g. { allow_leading_zeroes: true }).
• isJSON(str) - check if the string is valid JSON (note: uses JSON.parse).
• isLength(str, options) - check if the string's length falls in a range. options is an object which defaults to {min:0, max: undefined}. Note: this function takes into account surrogate pairs.
• isLowercase(str) - check if the string is lowercase.
• isMACAddress(str) - check if the string is a MAC address.
• isMD5(str) - check if the string is a MD5 hash.
• isMobilePhone(str, locale) - check if the string is a mobile phone number, (locale is one of ['ar-DZ', 'ar-SA', 'ar-SY', 'cs-CZ', 'de-DE', 'da-DK', 'el-GR', 'en-AU', 'en-GB', 'en-HK', 'en-IN', 'en-NZ', 'en-US', 'en-CA', 'en-ZA', 'en-ZM', 'es-ES', 'fi-FI', 'fr-FR', 'hu-HU', 'it-IT', 'ja-JP', 'ms-MY', 'nb-NO', 'nn-NO', 'pl-PL', 'pt-PT', 'ru-RU', 'sr-RS', 'tr-TR', 'vi-VN', 'zh-CN', 'zh-TW']).
• isMongoId(str) - check if the string is a valid hex-encoded representation of a MongoDB ObjectId.
• isMultibyte(str) - check if the string contains one or more multibyte chars.
• isNull(str) - check if the string is null (has a length of zero).
• isNumeric(str) - check if the string contains only numbers.
• isSurrogatePair(str) - check if the string contains any surrogate pairs chars.
• isURL(str [, options]) - check if the string is an URL. options is an object which defaults to { protocols: ['http','https','ftp'], require_tld: true, require_protocol: false, require_host: true, require_valid_protocol: true, allow_underscores: false, host_whitelist: false, host_blacklist: false, allow_trailing_dot: false, allow_protocol_relative_urls: false }.
• isUUID(str [, version]) - check if the string is a UUID (version 3, 4 or 5).
• isUppercase(str) - check if the string is uppercase.
• isVariableWidth(str) - check if the string contains a mixture of full and half-width chars.
• isWhitelisted(str, chars) - checks characters if they appear in the whitelist.
• matches(str, pattern [, modifiers]) - check if string matches the pattern. Either matches('foo', /foo/i) or matches('foo', 'foo', 'i').

Sanitizers

• blacklist(input, chars) - remove characters that appear in the blacklist. The characters are used in a RegExp and so you will need to escape some chars, e.g. blacklist(input, '\\[\\]').
• escape(input) - replace <, >, &, ', " and / with HTML entities.
• unescape(input) - replaces HTML encoded entities with <, >, &, ', " and /.
• ltrim(input [, chars]) - trim characters from the left-side of the input.
• normalizeEmail(email [, options]) - canonicalize an email address. options is an object which defaults to { lowercase: true, remove_dots: true, remove_extension: true }. With lowercase set to true, the local part of the email address is lowercased for all domains; the hostname is always lowercased and the local part of the email address is always lowercased for hosts that are known to be case-insensitive (currently only GMail). Normalization follows special rules for known providers: currently, GMail addresses have dots removed in the local part and are stripped of extensions (e.g. [e-mail] becomes [e-mail]) and all @googlemail.com addresses are normalized to @gmail.com.
• rtrim(input [, chars]) - trim characters from the right-side of the input.
• stripLow(input [, keep_new_lines]) - remove characters with a numerical value < 32 and 127, mostly control characters. If keep_new_lines is true, newline characters are preserved (\n and \r, hex 0xA and 0xD). Unicode-safe in JavaScript.
• toBoolean(input [, strict]) - convert the input string to a boolean. Everything except for '0', 'false' and '' returns true. In strict mode only '1' and 'true' return true.
• toDate(input) - convert the input string to a date, or null if the input is not a date.
• toFloat(input) - convert the input string to a float, or NaN if the input is not a float.
• toInt(input [, radix]) - convert the input string to an integer, or NaN if the input is not an integer.
• trim(input [, chars]) - trim characters (whitespace by default) from both sides of the input.
• whitelist(input, chars) - remove characters that do not appear in the whitelist. The characters are used in a RegExp and so you will need to escape some chars, e.g. whitelist(input, '\\[\\]').

XSS Sanitization

XSS sanitization was removed from the library in 2d5d6999.

For an alternative, have a look at Yahoo's xss-filters library or at DOMPurify.

Tests

$ npm test

Reading

Remember, validating can be troublesome sometimes. See A list of articles about programming assumptions commonly made that aren't true.

License (MIT)

Copyright (c) 2016 Chris O'Hara <[e-mail]>

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.