Async validation

[scotthovestadt]

Validation shouldn't need to throw an error. It doesn't fit with the way the rest of the code works. It should be allowed to return a promise or act on a callback like everything else does.

I need async validation.

@dthree Any concerns?

[dthree]

I recently updated it (like 2 days ago) so you can just return true, or false, or a message.

https://github.com/dthree/vorpal/wiki/api-|-vorpal.command#commandvalidatefunction

I agree with async as an option, sorry, I just hadn't gotten to it. :+1: on implementing.

[JeffSpies]

What's the status of this one? Still interested? I'd also like async validation.