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luhn-generator

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A generator of numbers that passes the validation of Luhn algorithm or Luhn formula, also known as the 'modulus 10' or 'mod 10' algorithm

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'use strict'; const preserveCamelCase = string => { let isLastCharLower = false; let isLastCharUpper = false; let isLastLastCharUpper = false; for (let i = 0; i < string.length; i++) { const character = string[i]; if (isLastCharLower && /[a-zA-Z]/.test(character) && character.toUpperCase() === character) { string = string.slice(0, i) + '-' + string.slice(i); isLastCharLower = false; isLastLastCharUpper = isLastCharUpper; isLastCharUpper = true; i++; } else if (isLastCharUpper && isLastLastCharUpper && /[a-zA-Z]/.test(character) && character.toLowerCase() === character) { string = string.slice(0, i - 1) + '-' + string.slice(i - 1); isLastLastCharUpper = isLastCharUpper; isLastCharUpper = false; isLastCharLower = true; } else { isLastCharLower = character.toLowerCase() === character && character.toUpperCase() !== character; isLastLastCharUpper = isLastCharUpper; isLastCharUpper = character.toUpperCase() === character && character.toLowerCase() !== character; } } return string; }; const camelCase = (input, options) => { if (!(typeof input === 'string' || Array.isArray(input))) { throw new TypeError('Expected the input to be `string | string[]`'); } options = Object.assign({ pascalCase: false }, options); const postProcess = x => options.pascalCase ? x.charAt(0).toUpperCase() + x.slice(1) : x; if (Array.isArray(input)) { input = input.map(x => x.trim()) .filter(x => x.length) .join('-'); } else { input = input.trim(); } if (input.length === 0) { return ''; } if (input.length === 1) { return options.pascalCase ? input.toUpperCase() : input.toLowerCase(); } const hasUpperCase = input !== input.toLowerCase(); if (hasUpperCase) { input = preserveCamelCase(input); } input = input .replace(/^[_.\- ]+/, '') .toLowerCase() .replace(/[_.\- ]+(\w|$)/g, (_, p1) => p1.toUpperCase()) .replace(/\d+(\w|$)/g, m => m.toUpperCase()); return postProcess(input); }; module.exports = camelCase; // TODO: Remove this for the next major release module.exports.default = camelCase;