Contents

'use strict';

function isValid(number) {
  number = number.replace(/\s/g, '');
  const digits = [...number];

  const sum = digits
    // convert to integers
    .map(d => parseInt(d, 10))
    // double even positions (odd indexes)
    .map((d, i) => {
      if (i % 2 !== 0) {
        return d * 2;
      }
      return d;
    })
    // limit to digits less than 10
    .map(d => {
      if (d > 9) {
        return d - 9;
      }
      return d;
    })
    // sum all digits
    .reduce((d, acc) => d + acc, 0);

  return sum > 0 && sum % 10 === 0;
}

function Luhn(number) {
  this.valid = isValid(number);
}

module.exports = Luhn;

Version data entries

251 entries across 251 versions & 1 rubygems

Version	Path
trackler-2.2.1.105	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.104	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.103	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.102	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.101	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.100	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.99	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.98	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.97	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.96	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.95	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.94	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.93	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.92	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.91	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.90	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.89	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.88	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.87	tracks/javascript/exercises/luhn/example.js
trackler-2.2.1.86	tracks/javascript/exercises/luhn/example.js