1.4.4

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<Formik />

<Formik> is a component that helps you with building forms. It uses a render props pattern made popular by libraries like React Motion and React Router.

Example

import React from 'react';
import { Formik } from 'formik';

const BasicExample = () => (
  <div>
    <h1>My Form</h1>
    <Formik
      initialValues={{ name: 'jared' }}
      onSubmit={(values, actions) => {
        setTimeout(() => {
          alert(JSON.stringify(values, null, 2));
          actions.setSubmitting(false);
        }, 1000);
      }}
      render={props => (
        <form onSubmit={props.handleSubmit}>
          <input
            type="text"
            onChange={props.handleChange}
            onBlur={props.handleBlur}
            value={props.values.name}
            name="name"
          />
          {props.errors.name && <div id="feedback">{props.errors.name}</div>}
          <button type="submit">Submit</button>
        </form>
      )}
    />
  </div>
);

Props

Reference

Props

Formik render methods and props

There are three ways to render things with <Formik />

  • <Formik component>
  • <Formik render>
  • <Formik children>

All three render methods will be passed the same props:

dirty: boolean

Returns true if values are not deeply equal from initial values, false otherwise. dirty is a readonly computed property and should not be mutated directly.

errors: { [field: string]: string }

Form validation errors. Should match the shape of your form's values defined in initialValues. If you are using validationSchema (which you should be), keys and shape will match your schema exactly. Internally, Formik transforms raw Yup validation errors on your behalf. If you are using validate, then that function will determine the errors objects shape.

handleBlur: (e: any) => void

onBlur event handler. Useful for when you need to track whether an input has been touched or not. This should be passed to <input onBlur={handleBlur} ... />

DOM-only. Use setFieldTouched in React Native.

handleChange: (e: React.ChangeEvent<any>) => void

General input change event handler. This will update the values[key] where key is the event-emitting input's name attribute. If the name attribute is not present, handleChange will look for an input's id attribute. Note: "input" here means all HTML inputs.

DOM-only. Use setFieldValue in React Native.

handleReset: () => void

Reset handler. Will reset the form to its initial state. This should be passed to <button onClick={handleReset}>...</button>

handleSubmit: (e: React.FormEvent<HTMLFormEvent>) => void

Submit handler. This should be passed to <form onSubmit={props.handleSubmit}>...</form>. To learn more about the submission process, see Form Submission.

isSubmitting: boolean

Submitting state of the form. Returns true if submission is in progress and false otherwise. IMPORTANT: Formik will set this to true as soon as submission is attempted. To learn more about the submission process, see Form Submission.

isValid: boolean

Returns true if the there are no errors, or the result of isInitialValid the form if is in "pristine" condition (i.e. not dirty).

isValidating: boolean

Returns true if Formik is running validation during submission, or by calling [validateForm] directly false otherwise. To learn more about what happens with isValidating during the submission process, see Form Submission.

resetForm: (nextValues?: Values) => void

Imperatively reset the form. This will clear errors and touched, set isSubmitting to false, isValidating to false, and rerun mapPropsToValues with the current WrappedComponent's props or what's passed as an argument. The latter is useful for calling resetForm within componentWillReceiveProps.

setErrors: (fields: { [field: string]: string }) => void

Set errors imperatively.

setFieldError: (field: string, errorMsg: string) => void

Set the error message of a field imperatively. field should match the key of errors you wish to update. Useful for creating custom input error handlers.

setFieldTouched: (field: string, isTouched?: boolean, shouldValidate?: boolean) => void

Set the touched state of a field imperatively. field should match the key of touched you wish to update. Useful for creating custom input blur handlers. Calling this method will trigger validation to run if validateOnBlur is set to true (which it is by default). isTouched defaults to true if not specified. You can also explicitly prevent/skip validation by passing a third argument as false.

submitForm: () => void

Trigger a form submission.

submitCount: number

Number of times user tried to submit the form. Increases when handleSubmit is called, resets after calling handleReset. submitCount is readonly computed property and should not be mutated directly.

setFieldValue: (field: string, value: any, shouldValidate?: boolean) => void

Set the value of a field imperatively. field should match the key of values you wish to update. Useful for creating custom input change handlers. Calling this will trigger validation to run if validateOnChange is set to true (which it is by default). You can also explicitly prevent/skip validation by passing a third argument as false.

setStatus: (status?: any) => void

Set a top-level status to anything you want imperatively. Useful for controlling arbitrary top-level state related to your form. For example, you can use it to pass API responses back into your component in handleSubmit.

setSubmitting: (isSubmitting: boolean) => void

Set isSubmitting imperatively.

setTouched: (fields: { [field: string]: boolean }) => void

Set touched imperatively.

setValues: (fields: { [field: string]: any }) => void

Set values imperatively.

status?: any

A top-level status object that you can use to represent form state that can't otherwise be expressed/stored with other methods. This is useful for capturing and passing through API responses to your inner component.

status should only be modified by calling setStatus.

touched: { [field: string]: boolean }

Touched fields. Each key corresponds to a field that has been touched/visited.

values: { [field: string]: any }

Your form's values. Will have the shape of the result of mapPropsToValues (if specified) or all props that are not functions passed to your wrapped component.

validateForm: (values?: any) => Promise<FormikErrors<Values>>

Imperatively call your validate or validateSchema depending on what was specified. You can optionally pass values to validate against and this modify Formik state accordingly, otherwise this will use the current values of the form.

validateField: (field: string) => void

Imperatively call field's validate function if specified for given field. Formik will use the current field value.

component?: React.ComponentType<FormikProps<Values>>

<Formik component={ContactForm} />;

const ContactForm = ({
  handleSubmit,
  handleChange,
  handleBlur,
  values,
  errors,
}) => (
  <form onSubmit={handleSubmit}>
    <input
      type="text"
      onChange={handleChange}
      onBlur={handleBlur}
      value={values.name}
      name="name"
    />
    {errors.name && <div>{errors.name}</div>}
    <button type="submit">Submit</button>
  </form>
};

Warning: <Formik component> takes precendence over <Formik render> so don’t use both in the same <Formik>.

render: (props: FormikProps<Values>) => ReactNode

<Formik render={props => <ContactForm {...props} />} />

<Formik
  render={({ handleSubmit, handleChange, handleBlur, values, errors }) => (
    <form onSubmit={handleSubmit}>
      <input
        type="text"
        onChange={handleChange}
        onBlur={handleBlur}
        value={values.name}
        name="name"
      />
      {errors.name &&
        <div>
          {errors.name}
        </div>}
      <button type="submit">Submit</button>
    </form>
  )}
/>

children?: React.ReactNode | (props: FormikProps<Values>) => ReactNode

<Formik children={props => <ContactForm {...props} />} />

// or...

<Formik>
  {({ handleSubmit, handleChange, handleBlur, values, errors }) => (
    <form onSubmit={handleSubmit}>
      <input
        type="text"
        onChange={handleChange}
        onBlur={handleBlur}
        value={values.name}
        name="name"
      />
      {errors.name &&
        <div>
          {errors.name}
        </div>}
      <button type="submit">Submit</button>
    </form>
  )}
</Formik>

enableReinitialize?: boolean

Default is false. Control whether Formik should reset the form if initialValues changes (using deep equality).

isInitialValid?: boolean

Default is false. Control the initial value of isValid prop prior to mount. You can also pass a function. Useful for situations when you want to enable/disable a submit and reset buttons on initial mount.

initialValues: Values

Initial field values of the form, Formik will make these values available to render methods component as values.

Even if your form is empty by default, you must initialize all fields with initial values otherwise React will throw an error saying that you have changed an input from uncontrolled to controlled.

Note: initialValues not available to the higher-order component, use mapPropsToValues instead.

onReset?: (values: Values, formikBag: FormikBag) => void

Your optional form reset handler. It is passed your forms values and the "FormikBag".

onSubmit: (values: Values, formikBag: FormikBag) => void

Your form submission handler. It is passed your forms values and the "FormikBag", which includes an object containing a subset of the injected props and methods (i.e. all the methods with names that start with set<Thing> + resetForm) and any props that were passed to the wrapped component.

Note: errors, touched, status and all event handlers are NOT included in the FormikBag.

validate?: (values: Values) => FormikErrors<Values> | Promise<any>

Note: I suggest using validationSchema and Yup for validation. However, validate is a dependency-free, straightforward way to validate your forms.

Validate the form's values with function. This function can either be:

  1. Synchronous and return an errors object.
// Synchronous validation
const validate = values => {
  const 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;
};
  • Asynchronous and return a Promise that's error in an errors object
// Async Validation
const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));

const validate = values => {
  return sleep(2000).then(() => {
    const errors = {};
    if (['admin', 'null', 'god'].includes(values.username)) {
      errors.username = 'Nice try';
    }
    // ...
    if (Object.keys(errors).length) {
      throw errors;
    }
  });
};

validateOnBlur?: boolean

Default is true. Use this option to run validations on blur events. More specifically, when either handleBlur, setFieldTouched, or setTouched are called.

validateOnChange?: boolean

Default is true. Use this option to tell Formik to run validations on change events and change-related methods. More specifically, when either handleChange, setFieldValue, or setValues are called.

validationSchema?: Schema | (() => Schema)

A Yup schema or a function that returns a Yup schema. This is used for validation. Errors are mapped by key to the inner component's errors. Its keys should match those of values.

← Form SubmissionwithFormik() →