Common String Validator

The purpose of this module is to provide validators for commonly used strings. This module makes sure that these different kinds of strings are in the correct format so that they can be used without problems in an application.

Available Validators

Date validation

Validates a date string in three different formats:

• Short format
  • 10/01/2025
• Long format
  • January 10, 2025
• ISO standard format:
  • 2025-01-10

Email validation

Validates using the the RFC 5322 Internet Message Format standard.

Format : [email protected]

• Rules

  • The local name can only contain letters, numbers and ASCII printable characters (.!#$%&'*+-/=?^_`{|}~)
  • The domain name can only contains letters, numbers and dashes.
  • The Email string must contain exactly one "@" symbol.
  • No consecutive special characters.
  • No special character first, last or next to the "@" symbol.
  • Top level domain name must be at least 2 characters long.
  • Local part maximum length is 64 characters.
  • Domain name maximum length is 64 characters each.
  • Maximum total length is 254 characters.

• Valid Email examples

  • [email protected]
  • [email protected]
  • [email protected]

Password validation

Validates a password string against complexity requirements (uppercase, lowercase, number, special character) and a minimum length.

• Rules
  • Has a uppercase letter.
  • Has a lowercase letter.
  • Has a number.
  • Has a special character.
  • Is at least 12 characters long.

Username validation

Validates a username string to make sure that it is easy to read.

• Rules
  • Can only contain letters, dashes and underscores.
  • Must be between 3 and 12 characters long.
  • Cannot have consecutive dashes or underscores.

URL Validation

Validates an URL string to make sure it is in a usable format for HTTP requests. Only validates http or https schemes.

Format: scheme://[hostname][:port]/path[?query][#fragment]

• Valid URL examples
  • https://my.site.com
  • http://example:8000/home

Example use cases

• API endpoints
• Account creation
• User registration
• Content Management Systems

Installation

npm install common-string-validator

Code examples

Date validation

import { isValidDate } from 'common-string-validator';

// Correct ISO Standard Format
const isoDate = '2024-05-15';
console.log(`Is "${isoDate}" a valid date?`, isValidDate(isoDate));

// Output: Is "2024-05-15" a valid date? true


// Spelling mistake in long format
const longDate = 'Janry 13. 2007';
console.log(`Is "${longDate}" a valid date?`, isValidDate(longDate));

// Output: Is 'Janry 13. 2007' a valid date? false

Email validation

import { isValidEmail } from 'common-string-validator';

// Valid E-mail
const email = '[email protected]';
console.log(`Is "${email}" a valid E-mail?`, isValidEmail(email));

// Output: Is "[email protected]" a valid E-mail? true


// Invalid E-mail
const email = 'jo%[email protected]';
console.log(`Is "${email}" a valid E-mail?`, isValidEmail(email));

// Output: Is 'jo%[email protected]' a valid E-mail? false

Password validation

import { isValidPassword } from 'common-string-validator';

// Valid password
const password = 'Sklr99m##dLBB2';
console.log(`Is "${password}" a valid password?`, isValidPassword(password));

// Output: Is 'Sklr99m##dL' a valid password? true


/ Invalid password
const password = 'abc123';
console.log(`Is "${password}" a valid password?`, isValidPassword(password));

// Output: Is 'abc123' a valid password? false

Username validation

import { isValidUsername } from 'common-string-validator';

// Valid password
const username = 'Johnny';
console.log(`Is "${username}" a valid username?`, isValidUsername(username));

// Output: Is 'Johnny' a valid username? true


// Invalid username
const username = 'J@nne__L#rss0n';
console.log(`Is "${username}" a valid username?`, isValidUsername(username));

// Output: Is 'J@nne__L#rss0n' a valid username? false

URL validation

import { isValidUrl } from 'common-string-validator';

// Valid URL
const url = 'https://company-name.work.org';
console.log(`Is "${url}" a valid URL?`, isValidUrl(url));

// Output: Is 'https://company-name.work.org' a valid URL? true


// Invalid URL
const url = 'https://company..name.work.c';
console.log(`Is "${username}" a valid username?`, isValidUrl(url));

// Output: Is 'Johnny' a valid url? false

License

This project is licensed under the MIT License.