"Tag" boolean

[cyrilchapon]

What about a "booleanTag" type, which would match value against variable presence only ?

I mean having a simple (VAR != null) (loose null or undefined, roughly means "presence") check that would allow anything, (including 0 or "") as value to be truthy. Acting like a --param tag and simpler booleans.

This shouldn't be mixed with the true boolean type though, IMHO, as they are pretty different

command	!!VAR
VAR="" node script.js	true
VAR=0 node script.js	true
VAR= node script.js	true
node script.js	false

const myenv = envalid({ 
  ...process.env,
  VAR: undefined
})

// myenv.VAR === false

const myenv = envalid({ 
  ...process.env,
  VAR: null
})

// myenv.VAR === false

[af]

I personally don't think this is generally useful enough to be included with the library, although I think it should be possible to add to your own project as a custom validator. Thanks for the suggestion though!