React Formik : how to use custom onChange and onBlur

I’m starting out with the formik library for react, and I can’t figure out the usage of the props handleChange and handleBlur.

According to the docs, handleBlur can be set as a prop on a <Formik/>, and then has to be passed manually down to the <input/>.

I’ve tried that, with no success : (I’m keeping the code about handleBlur for more clarity)

import React from "react";
import { Formik, Field, Form } from "formik";
import { indexBy, map, compose } from "ramda";
import { withReducer } from "recompose";

const MyInput = ({ field, form, handleBlur, ...rest }) =>
  <div>
    <input {...field} onBlur={handleBlur} {...rest} />
    {form.errors[field.name] &&
      form.touched[field.name] &&
      <div>
        {form.errors[field.name]}
      </div>}
  </div>;

const indexById = indexBy(o => o.id);
const mapToEmpty = map(() => "");

const EmailsForm = ({ fieldsList }) =>
  <Formik
    initialValues={compose(mapToEmpty, indexById)(fieldsList)}
    validate={values => {
      // console.log("validate", { values });
      const errors = { values };
      return errors;
    }}
    onSubmit={values => {
      console.log("onSubmit", { values });
    }}
    handleBlur={e => console.log("bluuuuurr", { e })}
    render={({ isSubmitting, handleBlur }) =>
      <Form>
        <Field
          component={MyInput}
          name="email"
          type="email"
          handleBlur={handleBlur}
        />
        <button type="submit" disabled={isSubmitting}>
          Submit
        </button>
      </Form>}
  />;

What is wrong with this approach ? How are handleBlur and handleChange actually supposed to be used ?

Answer

You’ll need to remove the first handleBlur from Formik as blur event is only valid on the field level and do something like the following in your Field element:

<Field
    component={MyInput}
    name="email"
    type="email"
    onBlur={e => {
        // call the built-in handleBur
        handleBlur(e)
        // and do something about e
        let someValue = e.currentTarget.value
        ...
    }}
/>

See https://github.com/jaredpalmer/formik/issues/157

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Answer