多个字段上的formik验证

import React from 'react';
import { Formik, Form, Field, ErrorMessage } from 'formik';
import * as Yup from 'yup';

const validationSchema = Yup.object({
  firstName: Yup.string()
    .max(15, 'Must be 15 characters or less')
    .required('Required'),
  lastName: Yup.string()
    .max(25, 'Must be 25 characters or less')
    .required('Required'),
  email: Yup.string()
    .email('Invalid email address')
    .required('Required'),
});

const MyForm = () => (
  <Formik
    initialValues={{ firstName: '', lastName: '', email: '' }}
    validationSchema={validationSchema}
    onSubmit={(values, { setSubmitting }) => {
      setTimeout(() => {
        alert(JSON.stringify(values, null, 2));
        setSubmitting(false);
      }, 400);
    }}
  >
    {({ isSubmitting }) => (
      <Form>
        <Field type="text" name="firstName" />
        <ErrorMessage name="firstName" component="div" />

        <Field type="text" name="lastName" />
        <ErrorMessage name="lastName" component="div" />

        <Field type="email" name="email" />
        <ErrorMessage name="email" component="div" />

        <button type="submit" disabled={isSubmitting}>
          Submit
        </button>
      </Form>
    )}
  </Formik>
);

export default MyForm;

<Formik
  // ...
  validateOnChange={true}
  validateOnBlur={true}
  // ...
>
  // ...
</Formik>

onSubmit={(values, { setSubmitting, validateForm }) => {
  validateForm().then(errors => {
    if (Object.keys(errors).length === 0) {
      // 表单验证通过，执行提交逻辑
    }
  });
}}