cdigit: Check Digit Algorithms in JS


cdigit - Collection of check digit algorithms implemented in JavaScript

Synopsis

Node.js:

``javascript
import { luhn } from "cdigit";

// Luhn (a.k.a. Mod 10) algorithm
console.log(luhn.compute("1234")); // "4"
console.log(luhn.generate("1234")); // "12344"
console.log(luhn.validate("12344")); // true
`

Command-line:

`bash


Damm algorithm


npx cdigit --algo damm compute 1234
npx cdigit --algo damm generate 1234
npx cdigit --algo damm validate 12340
`

Supported Algorithms

$3

| Algorithm | cdigit name | Input string | Check character(s) |
| ---------- | ----------- | ------------- | ------------------ |
| [Luhn] | luhn | Numeric (0-9) | 1 digit (0-9) |
| [Verhoeff] | verhoeff | Numeric (0-9) | 1 digit (0-9) |
| [Damm] | damm | Numeric (0-9) | 1 digit (0-9) |

[Luhn]: https://en.wikipedia.org/wiki/Luhn_algorithm
[Verhoeff]: https://en.wikipedia.org/wiki/Verhoeff_algorithm
[Damm]: https://en.wikipedia.org/wiki/Damm_algorithm

$3

ISO/IEC 7064 describes eight generic check digit (character) systems for
numeric, alphabetic, and alphanumeric strings. ISO/IEC 7064 specifies two types
of systems that use the same algorithm with different parameters: Pure systems
(MOD 11-2, MOD 37-2, MOD 97-10, MOD 661-26, and MOD 1271-36) and Hybrid systems
(MOD 11,10, MOD 27,26, and MOD 37,36).

| Algorithm | cdigit name | Input string | Check character(s) |
| ------------------------- | ----------- | --------------------- | ----------------------------------- |
| ISO/IEC 7064, MOD 11-2 | mod11_2 | Numeric (0-9) | 1 digit or 'X' (0-9X) |
| ISO/IEC 7064, MOD 37-2 | mod37_2 | Alphanumeric (0-9A-Z) | 1 digit, letter, or '\' (0-9A-Z\) |
| ISO/IEC 7064, MOD 97-10 | mod97_10 | Numeric (0-9) | 2 digits (0-9) |
| ISO/IEC 7064, MOD 661-26 | mod661_26 | Alphabetic (A-Z) | 2 letters (A-Z) |
| ISO/IEC 7064, MOD 1271-36 | mod1271_36 | Alphanumeric (0-9A-Z) | 2 digits or letters (0-9A-Z) |
| ISO/IEC 7064, MOD 11,10 | mod11_10 | Numeric (0-9) | 1 digit (0-9) |
| ISO/IEC 7064, MOD 27,26 | mod27_26 | Alphabetic (A-Z) | 1 letter (A-Z) |
| ISO/IEC 7064, MOD 37,36 | mod37_36 | Alphanumeric (0-9A-Z) | 1 digit or letter (0-9A-Z) |

[ISO/IEC 7064]: https://www.iso.org/standard/31531.html

$3

GTINs are internationally unified product identification numbers that are often
(or historically) referred to as [UPC], [EAN], [ISBN]-13, etc. GTINs have
several variations in length but share the identical check digit algorithm;
therefore, cdigit currently provides only one generic gtin object for GTINs
and other [GS1 data structures]. Note that the gtin object does not check the
length or semantic validity of a given GTIN string.

| Algorithm | cdigit name | Input string | Check character(s) | Also known as |
| --------- | ----------- | ------------- | ------------------ | ------------------------- |
| GTIN-8 | gtin | Numeric (0-9) | 1 digit (0-9) | EAN-8 |
| GTIN-12 | gtin | Numeric (0-9) | 1 digit (0-9) | UPC, UPC-A |
| GTIN-13 | gtin | Numeric (0-9) | 1 digit (0-9) | EAN, [JAN], ISBN-13, etc. |
| GTIN-14 | gtin | Numeric (0-9) | 1 digit (0-9) | EAN, UCC-14 |

[GTIN]: https://www.gs1.org/standards/id-keys/gtin
[UPC]: https://en.wikipedia.org/wiki/Universal_Product_Code
[EAN]: https://en.wikipedia.org/wiki/International_Article_Number
[ISBN]: https://en.wikipedia.org/wiki/International_Standard_Book_Number
[GS1 data structures]: https://www.gs1.org/standards/id-keys
[JAN]: https://en.wikipedia.org/wiki/International_Article_Number#Japanese_Article_Number

Usage - Node.js

Load algorithm objects using the cdigit names listed in
Supported Algorithms section.

`javascript
import { mod97_10 } from "cdigit";
`

Algorithm objects implement the following methods:

$3

Checks if a protected string is valid per the algorithm.

`javascript
console.log(mod97_10.validate("123482")); // true
`

$3

Generates the protected string from the argument using the algorithm. The
generated string consists of the original bare string and computed check
character(s), which are combined in accordance with the algorithm.

`javascript
console.log(mod97_10.generate("1234")); // "123482"
`

$3

Generates the check character(s) from the argument using the algorithm. Unlike
generate(), this method returns the check character(s) only.

`javascript
console.log(mod97_10.compute("1234")); // "82"
`

$3

Generates the check character(s) from the argument using the algorithm. This
method is an alphabet-independent equivalent of compute(), where the return
value and argument are both represented as arrays of each digit's numerical
value.

`javascript
console.log(mod97_10.computeFromNumVals([1, 2, 3, 4])); // [8, 2]
`

See example.js for usage examples.

Usage - Command-line

`
Usage: cdigit [options] [command]

Options:
-a, --algo specify check digit algorithm by name
-h, --help display help for command

Commands:
validate check if string is valid
generate append check character(s) to string
compute print check character(s) computed from string
`

-a, --algo option accepts the names listed in Supported Algorithms
section and defaults to luhn or the value of
CDIGIT_CLI_DEFAULT_ALGO` environment variable (if set).

License

Copyright (c) 2018-2023 LiosK

Licensed under either of

- Apache License, Version 2.0
- MIT license

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.

See Also

- API Documentation
- Run tests on your browser