How can I implement advanced validation in Formik?

How can I implement advanced validation in Formik?

You can use the validate prop in Formik to create custom validation logic. Would you like an example?

Yes, please provide an example of custom validation.

Sure! You can define a validation function that checks for specific conditions, like this:

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.

How do I integrate this validation function into my Formik form?

You can pass the validate function to the Formik component like this:

<Formik
  initialValues={{ email: '' }}
  validate={validate}
  onSubmit={values => { /* handle submit */ }}
>
  {/* form fields */}
</Formik>