Allow empty string but fail on undefined

According to README, it should be possible to require empty string:

To allow empty strings but fail on undefined values use: string().required().min(0)

However, this does not seem to work:

const yup = require("yup")

const okString = 'foo';
const shouldBeOkString = '';
let nokString;

const schema = yup.string().required().min(0);

console.log(await schema.isValid(okString)); // true
console.log(await schema.isValid(shouldBeOkString)); // false <--
console.log(await schema.isValid(nokString)); // false

Same with yup.array().required().min(0) won’t allow [].

Am I missing something?

[tnrich]

I don’t see how to do the old

string().required().min(0) 

case anymore. Do I have to now provide a custom yup method? I made a SO question asking for help https://stackoverflow.com/questions/63943689/how-to-get-yup-string-to-require-string-of-any-length-including-0

Thanks!

[blasterbug]

In deed, string().required().min(0) fail miserably for empty strings.