Stringprep Profile for User Names and Passwords, rfc4013
const saslprep = require('saslprep')
saslprep('password\u00AD') // password
saslprep('password\u0007') // Error: prohibited character
saslprep(input: String, opts: Options): String
Normalize user name or password.
Options.allowUnassigned: bool
A special behavior for unassigned code points, see https://tools.ietf.org/html/rfc4013#section-2.5. Disabled by default.
MIT, 2017 (c) Dmitriy Tsvettsikh