node/deps/npm/node_modules/npm-user-validate/npm-user-validate.js

exports.email = email
exports.pw = pw
exports.username = username

var requirements = exports.requirements = {
  username: {
    lowerCase: 'Username must be lowercase',
    urlSafe: 'Username may not contain non-url-safe chars',
    dot: 'Username may not start with "."'
  },
  password: {
    badchars: 'Password passwords cannot contain these characters: \'!:@"'
  },
  email: {
    valid: 'Email must be an email address'
  }
};

function username (un) {
  if (un !== un.toLowerCase()) {
    return new Error(requirements.username.lowerCase)
  }

  if (un !== encodeURIComponent(un)) {
    return new Error(requirements.username.urlSafe)
  }

  if (un.charAt(0) === '.') {
    return new Error(requirements.username.dot)
  }

  return null
}

function email (em) {
  if (!em.match(/^.+@.+\..+$/)) {
    return new Error(requirements.email.valid)
  }

  return null
}

function pw (pw) {
  if (pw.match(/['!:@"]/)) {
    return new Error(requirements.password.badchars)
  }

  return null
}