Синхронизация и асинхронная проверка
// Synchronous validation
const validate = (values, props /* only available when using withFormik */) => {
let errors = {};
if (!values.email) {
errors.email = 'Required';
} else if (!/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i.test(values.email)) {
errors.email = 'Invalid email address';
}
//...
return errors;
};
// Async Validation
const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
const validate = (values, props /* only available when using withFormik */) => {
return sleep(2000).then(() => {
let errors = {};
if (['admin', 'null', 'god'].includes(values.username)) {
errors.username = 'Nice try';
}
// ...
if (Object.keys(errors).length) {
throw errors;
}
});
};
Схема проверки YUP
import React from 'react';
import { Formik, Form, Field } from 'formik';
import * as Yup from 'yup';
const SignupSchema = Yup.object().shape({
firstName: Yup.string()
.min(2, 'Too Short!')
.max(50, 'Too Long!')
.required('Required'),
lastName: Yup.string()
.min(2, 'Too Short!')
.max(50, 'Too Long!')
.required('Required'),
email: Yup.string()
.email('Invalid email')
.required('Required'),
});
export const ValidationSchemaExample = () => (
<div>
<h1>Signup</h1>
<Formik
initialValues={{
firstName: '',
lastName: '',
email: '',
}}
validationSchema={SignupSchema}
onSubmit={values => {
// same shape as initial values
console.log(values);
}}
>
{({ errors, touched }) => (
<Form>
<Field name="firstName" />
{errors.firstName && touched.firstName ? (
<div>{errors.firstName}</div>
) : null}
<Field name="lastName" />
{errors.lastName && touched.lastName ? (
<div>{errors.lastName}</div>
) : null}
<Field name="email" type="email" />
{errors.email && touched.email ? <div>{errors.email}</div> : null}
<button type="submit">Submit</button>
</Form>
)}
</Formik>
</div>
);
Ссылка: https://jaredpalmer.com/formik/docs/guides/validation