code: function readSetupToken (cb) {
    var token
    var write = false
  
    try {
      // try to read setup token from filesystem
      token = keygen.loadSetupToken()
      // if token is blank, try to generate a new token and save it
      if (!token.trim()) {
        write = true
      }
    } catch (err) {
      // if unable to read, try to generate a new token and save it
      write = true
    }
  
    if (write) {
      try {
        token = keygen.generateSetupToken()
      } catch (err) {
        // if we can't write the token to disk, something is very wrong
        return cb(err)
      }
    }
  
    // return the token
    cb(null, token)
  }
docs: Read setup token from filesystem or create if missing