Yup: Validate only when field not empty \ compare fields are equal

[odesey]

If this has been answered before, I apologies. I did various searches but came up empty.

export const yupTest = yup.object().shape({
  firstName: yup.string().required('Please enter your First Name'),
  lastName: yup.string().notRequired().test('last_name', 'Last Name test message', function(value) {
    if (!!value) {
      return false; // this works as expected
    }
    return true; // <-- How do I do a sync test here like yup.string(value).min(2)
  }),
});

I have a few fields and only want to validate some IF the user has entered some data.

Also, how can I check if 2 fields are equal to each other (password === confirmPassword)?

[jquense]

mosts tests already ignore empty values, generally you can just add the test, and if you wnat to validate it being there also add required()

[odesey]

Thanks for your quick response!

I think I resolved the first question (although I am not sure if it's correct based on your response)

 export const yupTest = yup.object().shape({
  firstName: yup.string().required('Please enter your First Name'),
  lastName: yup.string().notRequired().test('last_name', 'Last Name test message', function(value) {
    if (!!value) {
      const schema = yup.string().min(2);
      return schema.isValidSync(value);
    }
    return true;
  }),
 });

What about comparing two fields for equality?

Thanks.

[jquense]

There are a few past issues on that, tho a bit hard to find. You can use ref() like string().oneOf([yup.ref('otherPassword')])

[odesey]

This did the trick:

.oneOf([yup.ref('password'), null], "Passwords don't match")

Thanks for your help!