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 is 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

Client-side usage

The library can be loaded as a script and supports AMD

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

Validators

• equals(str, comparison) - check if the string matches the comparison.
• contains(str, seed) - check if the string contains the seed.
• matches(str, pattern [, modifiers]) - check if string matches the pattern. Either matches('foo', /foo/i) or matches('foo', 'foo', 'i').
• isEmail(str) - check if the string is an email.
• isURL(str) - check if the string is an URL.
• isIP(str [, version]) - check if the string is an IP (version 4 or 6).
• isAlpha(str) - check if the string contains only letters (a-zA-Z).
• isNumeric(str) - check if the string contains only numbers.
• isAlphanumeric(str) - check if the string contains only letters and numbers.
• isHexadecimal(str) - check if the string is a hexadecimal number.
• isHexColor(str) - check if the string is a hexadecimal color.
• isLowercase(str) - check if the string is lowercase.
• isUppercase(str) - check if the string is uppercase.
• isInt(str) - check if the string is an integer.
• isFloat(str) - check if the string is a float.
• isDivisibleBy(str, number) - check if the string is a number that's divisible by another.
• isNull(str) - check if the string is null.
• isLength(str, min [, max]) - check if the string's length falls in a range.
• isUUID(str [, version]) - check if the string is a UUID (version 3, 4 or 5).
• isDate(str) - check if the string is a date.
• isAfter(str [, date]) - check if the string is a date that's after the specified date (defaults to now).
• isBefore(str [, date]) - check if the string is a date that's before the specified date.
• isIn(str, values) - check if the string is in a array of allowed values.
• isCreditCard(str) - check if the string is a credit card.
• isISBN(str [, version]) - check if the string is an ISBN (version 10 or 13).

Sanitizers

• toString(input) - convert the input to a string.
• toDate(input) - convert the input to a date, or null if the input is not a date.
• toFloat(input) - convert the input to a float, or NaN if the input is not a float.
• toInt(input [, radix]) - convert the input to an integer, or NaN if the input is not an integer.
• toBoolean(input [, strict) - convert the input to a boolean. Everything except for '0', 'false' and '' returns true. In strict mode only '1' and 'true' return true.
• trim(input [, chars]) - trim characters (whitespace by default) from both sides of the input.
• ltrim(input [, chars]) - trim characters from the left-side of the input.
• rtrim(input [, chars]) - trim characters from the right-side of the input.
• escape(input) - replace <, >, & and " with HTML entities.
• whitelist(input, chars) - remove characters that do not appear in the whitelist.
• blacklist(input, chars) - remove characters that appear in the blacklist.

Strings only

This library validates and sanitizes strings only. All input will be coerced to a string using the following rules

• Call the toString property if available.
• Replace null, undefined or NaN with an empty string.
• Everything else is coerced with input + ''.

Extensions

You can add your own validators using validator.extend(name, fn)

validator.extend('isFinite', function (str) {
    return isFinite(str);
});

Note that the first argument will be automatically coerced to a string.

Deprecations

Version 3 of the library deprecated some functionality

• XSS sanitizer: Here's why. Use Google Caja instead.
• Entity encoding: Use fb55/entities or substack/node-ent.
• Validator chaining: The API was too unintuitive. I'd prefer to let users create their own higher-level patterns from the provided building blocks.

Tests

• make test - run the test suite.
• make test V=1 - run the test suite with added verbosity.
• make test TEST=pattern - run tests that match a pattern.
• make coverage - run a coverage analysis tool.
• make lint - run a lint tool.

License (MIT)

Copyright (c) 2014 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.