cdigit
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Collection of check digit algorithms implemented in JavaScript
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cdigit: Check Digit Algorithms in JS
cdigit - Collection of check digit algorithms implemented in JavaScript
Synopsis
Node.js:
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:
# Damm algorithm
npx cdigit --algo damm compute 1234
npx cdigit --algo damm generate 1234
npx cdigit --algo damm validate 12340
Supported Algorithms
Generic Algorithms
| 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) |
ISO/IEC 7064 Family
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) |
GTIN (Global Trade Item Number) Family
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 |
Usage - Node.js
Load algorithm objects using the cdigit names listed in Supported Algorithms section.
import { mod97_10 } from "cdigit";
Algorithm objects implement the following methods:
validate(strWithCheckChars: string): boolean
Checks if a protected string is valid per the algorithm.
console.log(mod97_10.validate("123482")); // true
generate(strWithoutCheckChars: string): string
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.
console.log(mod97_10.generate("1234")); // "123482"
compute(strWithoutCheckChars: string): string
Generates the check character(s) from the argument using the algorithm. Unlike
generate()
, this method returns the check character(s) only.
console.log(mod97_10.compute("1234")); // "82"
computeFromNumVals(numValsWithoutCheckChars: number[]): number[]
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.
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 <name> specify check digit algorithm by name
-h, --help display help for command
Commands:
validate <string> check if string is valid
generate <string> append check character(s) to string
compute <string> print check character(s) computed from string
-a, --algo <name>
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
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.