creditcardutils

A general purpose javascript library for credit card number validation and formatting. Based on jondavidjohn/payform and jquery.payment. Usable in React Native and Node.

Supported card types:

• Visa
• MasterCard
• American Express
• Diners Club
• Discover
• UnionPay
• JCB
• Visa Electron
• Maestro
• Forbrugsforeningen
• Dankort

(Custom card types are also supported)

Installation / Usage

npm (Node and Browserify)

npm install creditcardutils --save

var creditcardutils = require('creditcardutils');

// Format input for card number 
creditcardutils.formatCardNumber(input); //=> returns formatted card number

// Validate a credit card number
creditcardutils.validateCardNumber('4242 4242 4242 4242'); //=> true

// Get card type from number
creditcardutils.parseCardType('4242 4242 4242 4242'); //=> 'visa'

API

General Formatting and Validation

creditcardutils.formatCardNumber(input)

Formats card numbers:

• Includes a space between every 4 digits
• Restricts input to numbers
• Limits to 16 numbers
• Supports American Express formatting

Example:

creditcardutils.formatCardNumber(input); //=>returns formatted card number

creditcardutils.validateCardNumber(number)

Validates a card number:

• Validates numbers
• Validates Luhn algorithm
• Validates length

Example:

creditcardutils.validateCardNumber('4242 4242 4242 4242'); //=> true

creditcardutils.validateCardExpiry(month, year)

Validates a card expiry:

• Validates numbers
• Validates in the future
• Supports year shorthand

Example:

creditcardutils.validateCardExpiry('05', '20'); //=> true
creditcardutils.validateCardExpiry('05', '2015'); //=> true
creditcardutils.validateCardExpiry('05', '05'); //=> false

creditcardutils.validateCardCVC(cvc, type)

Validates a card CVC:

• Validates number
• Validates length to 4

Example:

creditcardutils.validateCardCVC('123'); //=> true
creditcardutils.validateCardCVC('123', 'amex'); //=> true
creditcardutils.validateCardCVC('1234', 'amex'); //=> true
creditcardutils.validateCardCVC('12344'); //=> false

creditcardutils.parseCardType(number)

Returns a card type. Either:

• visa
• mastercard
• amex
• dinersclub
• discover
• unionpay
• jcb
• visaelectron
• maestro
• forbrugsforeningen
• dankort

The function will return null if the card type can't be determined.

Example:

creditcardutils.parseCardType('4242 4242 4242 4242'); //=> 'visa'
creditcardutils.parseCardType('hello world?'); //=> null

creditcardutils.parseCardExpiry(string)

Parses a credit card expiry in the form of MM/YYYY, returning an object containing the month and year. Shorthand years, such as 13 are also supported (and converted into the longhand, e.g. 2013).

creditcardutils.parseCardExpiry('03 / 2025'); //=> {month: 3: year: 2025}
creditcardutils.parseCardExpiry('05 / 04'); //=> {month: 5, year: 2004}

This function doesn't perform any validation of the month or year; use creditcardutils.validateCardExpiry(month, year) for that.

Custom Cards

creditcardutils.cards

Array of objects that describe valid card types. Each object should contain the following fields:

{
  // Card type, as returned by creditcardutils.parseCardType.
  type: 'mastercard',
  // Regex used to identify the card type. For the best experience, this should be
  // the shortest pattern that can guarantee the card is of a particular type.
  pattern: /^5[0-5]/,
  // Array of valid card number lengths.
  length: [16],
  // Array of valid card CVC lengths.
  cvcLength: [3],
  // Boolean indicating whether a valid card number should satisfy the Luhn check.
  luhn: true,
  // Regex used to format the card number. Each match is joined with a space.
  format: /(\d{1,4})/g
}

When identifying a card type, the array is traversed in order until the card number matches a pattern. For this reason, patterns with higher specificity should appear towards the beginning of the array.

Development

Please see CONTRIBUTING.md.