How can I implement custom validation messages in Formik?

How can I implement custom validation messages in Formik?

You can use the validate function in Formik to return custom error messages for your fields.

Can you show me an example of how to do that?

Sure! Here's a simple example:

const validate = values => {
  const errors = {};
  if (!values.email) {
    errors.email = 'Required';
  } else if (!/\S+@\S+\.\S+/.test(values.email)) {
    errors.email = 'Invalid email address';
  }
  return errors;
};

This function checks if the email field is empty or invalid and returns custom messages.

What if I want to customize messages for multiple fields?

You can extend the validate function to include checks for other fields as well. Just add more conditions for each field you want to validate.