<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.
import React from 'react';import { Formik } from 'formik';const BasicExample = () => (<div><h1>My Form</h1><FormikinitialValues={{ name: 'jared' }}onSubmit={(values, actions) => {setTimeout(() => {alert(JSON.stringify(values, null, 2));actions.setSubmitting(false);}, 1000);}}>{props => (<form onSubmit={props.handleSubmit}><inputtype="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>)}</Formik></div>);
There are 2 ways to render things with <Formik />
<Formik component><Formik children><Formik render>Each render methods will be passed the same props:
dirty: booleanReturns 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) => voidonBlur 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} ... />
handleChange: (e: React.ChangeEvent<any>) => voidGeneral 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.
handleReset: () => voidReset handler. Will reset the form to its initial state. This should be passed
to <button onClick={handleReset}>...</button>
handleSubmit: (e: React.FormEvent<HTMLFormEvent>) => voidSubmit handler. This should be passed to <form onSubmit={props.handleSubmit}>...</form>. To learn more about the submission process, see Form Submission.
isSubmitting: booleanSubmitting 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: booleanReturns true if there are no errors (i.e. the errors object is empty) and false otherwise.
Note:
isInitialValidwas deprecated in 2.x. However, for backwards compatibility, if theisInitialValidprop is specified,isValidwill returntrueif the there are noerrors, or the result ofisInitialValidof the form if it is in "pristine" condition (i.e. notdirty).
isValidating: booleanReturns 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: (nextInitialState?: FormikState<Values>) => voidImperatively reset the form. If nextInitialState is specified, Formik will set this state as the new "initial state" and use the related values of nextInitialState to update the form's initialValues as well as initialTouched, initialStatus, initialErrors. This is useful for altering the initial state (i.e. "base") of the form after changes have been made. If nextInitialState is not defined, then Formik will reset state to the original initial state. The latter is useful for calling resetForm within componentDidUpdate or useEffect.
setErrors: (fields: { [field: string]: string }) => voidSet errors imperatively.
setFieldError: (field: string, errorMsg: string) => voidSet 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) => voidSet 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: () => PromiseTrigger a form submission. The promise will be rejected if form is invalid.
submitCount: numberNumber 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) => voidSet 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) => voidSet 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) => voidSet isSubmitting imperatively. You would call it with setSubmitting(false) in your onSubmit handler to finish the cycle. To learn more about the submission process, see Form Submission.
setTouched: (fields: { [field: string]: boolean }, shouldValidate?: boolean) => voidSet touched imperatively. Calling this will trigger validation to run if validateOnBlur is set to true (which it is by default). You can also explicitly prevent/skip validation by passing a second argument as false.
setValues: (fields: { [field: string]: any }, shouldValidate?: boolean) => voidSet values imperatively. 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 second argument as false.
status?: anyA 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) => voidImperatively call field's validate function if specified for given field or run schema validation using Yup's schema.validateAt and the provided top-level validationSchema prop. 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}><inputtype="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>) => ReactNodeDeprecated in 2.x
<Formik render={props => <ContactForm {...props} />} /><Formikrender={({ handleSubmit, handleChange, handleBlur, values, errors }) => (<form onSubmit={handleSubmit}><inputtype="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}><inputtype="text"onChange={handleChange}onBlur={handleBlur}value={values.name}name="name"/>{errors.name &&<div>{errors.name}</div>}<button type="submit">Submit</button></form>)}</Formik>
enableReinitialize?: booleanDefault is false. Control whether Formik should reset the form if
initialValues changes (using deep equality).
isInitialValid?: booleanDeprecated in 2.x, use initialErrors instead
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.
initialErrors?: FormikErrors<Values>Initial field errors of the form, Formik will make these values available to
render methods component as errors.
Note: initialErrors is not available to the higher-order component withFormik, use
mapPropsToErrors instead.
initialStatus?: anyAn arbitrary value for the initial status of the form. If the form is reset, this value will be restored.
Note: initialStatus is not available to the higher-order component withFormik, use
mapPropsToStatus instead.
initialTouched?: FormikTouched<Values>Initial visitied fields of the form, Formik will make these values available to
render methods component as touched.
Note: initialTouched is not available to the higher-order component withFormik, use
mapPropsToTouched instead.
initialValues: ValuesInitial 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) => voidYour optional form reset handler. It is passed your forms values and the
"FormikBag".
onSubmit: (values: Values, formikBag: FormikBag) => void | Promise<any>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.
IMPORTANT: If
onSubmitis async, then Formik will automatically setisSubmittingtofalseon your behalf once it has resolved. This means you do NOT need to callformikBag.setSubmitting(false)manually. However, if youronSubmitfunction is synchronous, then you need to callsetSubmitting(false)on your own.
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:
errors object.// Synchronous validationconst 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;};
errors// Async Validationconst 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';}// ...return errors;});};
validateOnBlur?: booleanDefault is true. Use this option to run validations on blur events. More
specifically, when either handleBlur, setFieldTouched, or setTouched
are called.
validateOnChange?: booleanDefault 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.
validateOnMount?: booleanDefault is false. Use this option to tell Formik to run validations when the <Formik /> component mounts
and/or initialValues change.
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.
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