I have this in a few places...

joi.validate(option, {
    port : joi.number().integer().min(0).max(65535)
});

Given that joi is most commonly used for servers (related: string().hostname()) and port numbers are a standardized and commonly used thing, I would prefer for this to be built in.

joi.validate(option, {
    port : joi.number().port()
});

Beyond the readability and succinctness of it, I like that this would free my apps from having the 65535 constant, which people sometimes ask me about.

Thoughts?