index.js

function validate(vin) {
  vin = vin.toLowerCase();
  if (!/^[a-hj-npr-z0-9]{8}[0-9xX][a-hj-npr-z0-9]{8}$/.test(vin)) {
    return false;
  }

  var transliterationTable = {
    '0': 0,
    '1': 1,
    '2': 2,
    '3': 3,
    '4': 4,
    '5': 5,
    '6': 6,
    '7': 7,
    '8': 8,
    '9': 9,
    'a': 1,
    'b': 2,
    'c': 3,
    'd': 4,
    'e': 5,
    'f': 6,
    'g': 7,
    'h': 8,
    'j': 1,
    'k': 2,
    'l': 3,
    'm': 4,
    'n': 5,
    'p': 7,
    'r': 9,
    's': 2,
    't': 3,
    'u': 4,
    'v': 5,
    'w': 6,
    'x': 7,
    'y': 8,
    'z': 9
  };

  var weightsTable = [8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2];
  var sum = 0;

  for (var i = 0; i < vin.length; ++i) {
    sum += transliterationTable[vin.charAt(i)] * weightsTable[i];
  }

  var mod = sum % 11;
  return mod === 10 ? vin.charAt(8) === 'x' : vin.charAt(8) == mod;
}

module.exports = {
  validate: validate
};