Yup schema validation: Exclude a certain pattern in the method '.matches()'

Question

I want to make sure users don't fill in their username (pattern is a upercase or lowercase u, followed by 7-10 digits: U0000000)

In the following example, the regex itself does work. However in conjunction with the .matches() method it does not validate the field.

const schema = Yup.object()
  .shape({
    myField: Yup.string()
      .matches(/.*\d/, 'Should contain a digit') // <- this works
      .matches(/(?!.*[uU]\d{7,10})/, 'Should not contain a user ID') // <- this does not
  });

Answer 1

Turns out that matches will only validate an invalid error if the Regex you provide returns positive.

If you want to validate on a negative 'match' (a.k.a. not operator regex match), you can use the .test() method.

In the documentation it's not mentioned under string, but under mixed (source):

mixed.test(name: string, message: string | function, test: function): Schema

So in my example I ended up with:

const containsDeviceId = (string) => /d\d{7,10}/.test(string);
const schema = Yup.object()
  .shape({
    myField: Yup.string()
      .matches(/.*\d/, 'Should contain a digit')
      .test(
        'Should not contain a user ID',
        'Should not contain a user ID',
        (value) => !containsDeviceId(value)
      ),

Hope this helps someone.