Calculates Luhn Mod N check values
npm install calculate-luhn-mod-n!GitHub
!Node CI
!Node.js Package
Calculates Luhn Mod N check values
Code based on
with minimal modifications.
``sh`
npm install calculate-luhn-mod-n
Parameter | Description
--- | ---
codePointFromCharacter | Function to obtain a code point from a character
characterFromCodePoint | Function to obtain a character from a code point
n | Number of valid characters
input | Input string
The following example is based on the one found at
`javascript
const map = 'abcdef'; // Character to code-point map
const calculateLuhnModN = require('calculate-luhn-mod-n');
const checkCharacter = calculateLuhnModN(character => map.indexOf(character), codePoint => map[codePoint], map.length, 'abcdef'))
// checkCharacter === 'e'
`
The following example uses JavaScript native functions (parseInt and toString) to do the mapping based on radix/mod 36.
`javascript
const calculateLuhnModN = require('calculate-luhn-mod-n');
function appendLuhnMod36(input) {
const radix = 36;
return input + calculateLuhnModN(character => Number.parseInt(character, radix), codePoint => codePoint.toString(radix).toUpperCase(), radix, input);
}
const output = appendLuhnMod36('1134806PJFB000010013CD18');
// output === '1134806PJFB000010013CD18D'
`
The following example builds upon the previous one and demonstrates a possible way to do validation against an arbitrary regular expression before calculating the check character.
`javascript
const calculateLuhnModN = require('calculate-luhn-mod-n');
function appendLuhnMod36(input) {
const radix = 36;
const pattern = /^([A-Z]|\d){4}\d{3}([A-Z]|\d){15}\d{2}$/;
if (!pattern.test(input)) {
throw new Error('Invalid identifier format!');
}
return input + calculateLuhnModN(character => Number.parseInt(character, radix), codePoint => codePoint.toString(radix).toUpperCase(), radix, input);
}
const output = appendLuhnMod36('1134806PJFB000010013CD18');
// output === '1134806PJFB000010013CD18D'
``