How to customize yup validation messages?

Question

Most answers I have seen customize yup validation messages when defining a schema, e.g.

const personSchema = yup.object().shape({
    firstName: yup.string().required('First name is a required field'),
    lastName: yup.string().required('Last name is a required field'),
});

But what if I want to customize the default validation message itself? For example, required fields should always render a fixed string "Required field".

Answer 1

You could do it by using setLocale function from yup like this:

  import * as Yup from 'yup';

  Yup.setLocale({
    mixed: {
      required: 'Required Field',
    },
  });

For more information check the documentation: https://github.com/jquense/yup

The section Using a custom locale dictionary is what you need.