Alias single letter to negated boolean option

[verhovsky]

I want to have --test set test: true but then also have an alias -T set test: false. Can I do this with yargs? I tried this:

> parser = require('yargs-parser')
> parser('-T', {alias: {T: 'no-test'}, boolean: ['test']})
{ _: [], T: true, 'no-test': true, noTest: true }