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final-form

🏁 Framework agnostic, high performance, subscription-based form state management

4.16.0
Source
npm

Version published: 5 years ago

Weekly downloads: 404K; increased by0.75%

Maintainers: 1

Weekly downloads

Created: 7 years ago

What is final-form?

Final Form is a framework-agnostic library for managing form state in JavaScript. It provides a simple API for handling form validation, submission, and state management, making it easier to build complex forms with minimal boilerplate code.

What are final-form's main functionalities?

Form State Management

Final Form provides a simple way to manage form state. The `Form` component handles the form submission, while the `Field` component is used to define form fields. The form state is managed internally and can be accessed via the `render` prop.

const { Form, Field } = require('react-final-form');

const MyForm = () => (
  <Form
    onSubmit={formValues => {
      console.log(formValues);
    }}
    render={({ handleSubmit }) => (
      <form onSubmit={handleSubmit}>
        <Field name="firstName" component="input" placeholder="First Name" />
        <Field name="lastName" component="input" placeholder="Last Name" />
        <button type="submit">Submit</button>
      </form>
    )}
  />
);

Validation

Final Form allows you to easily add validation to your forms. The `validate` function is used to define validation rules, and it returns an object containing any validation errors. These errors are then displayed in the form.

const { Form, Field } = require('react-final-form');

const validate = values => {
  const errors = {};
  if (!values.firstName) {
    errors.firstName = 'Required';
  }
  if (!values.lastName) {
    errors.lastName = 'Required';
  }
  return errors;
};

const MyForm = () => (
  <Form
    onSubmit={formValues => {
      console.log(formValues);
    }}
    validate={validate}
    render={({ handleSubmit }) => (
      <form onSubmit={handleSubmit}>
        <Field name="firstName" component="input" placeholder="First Name" />
        <Field name="lastName" component="input" placeholder="Last Name" />
        <button type="submit">Submit</button>
      </form>
    )}
  />
);

Field-Level Validation

Final Form supports field-level validation, allowing you to define validation rules for individual fields. The `validate` prop on the `Field` component is used to specify the validation function for that field.

const { Form, Field } = require('react-final-form');

const required = value => (value ? undefined : 'Required');

const MyForm = () => (
  <Form
    onSubmit={formValues => {
      console.log(formValues);
    }}
    render={({ handleSubmit }) => (
      <form onSubmit={handleSubmit}>
        <Field name="firstName" component="input" placeholder="First Name" validate={required} />
        <Field name="lastName" component="input" placeholder="Last Name" validate={required} />
        <button type="submit">Submit</button>
      </form>
    )}
  />
);

Form Submission

Final Form makes it easy to handle form submission. The `onSubmit` prop on the `Form` component is used to define the submission handler, which receives the form values as an argument.

const { Form, Field } = require('react-final-form');

const MyForm = () => (
  <Form
    onSubmit={formValues => {
      console.log('Form submitted with values:', formValues);
    }}
    render={({ handleSubmit }) => (
      <form onSubmit={handleSubmit}>
        <Field name="firstName" component="input" placeholder="First Name" />
        <Field name="lastName" component="input" placeholder="Last Name" />
        <button type="submit">Submit</button>
      </form>
    )}
  />
);

Other packages similar to final-form

🏁 Final Form

✅ Zero dependencies *

✅ Framework agnostic

✅ Opt-in subscriptions - only update on the state you need!

✅ 💥 4.8k gzipped 💥

💬 Give Feedback on Final Form 💬

In the interest of making 🏁 Final Form the best library it can be, we'd love your thoughts and feedback.

Take a quick survey.

Installation

npm install --save final-form

yarn add final-form

Zero Dependencies

Technically there is a dependency on @babel/runtime, but this actually makes your final bundle size smaller by sharing common babel code between libraries.

Getting Started

🏁 Final Form works on subscriptions to perform updates based on the Observer pattern. Both form and field subscribers must specify exactly which parts of the form state they want to receive updates about.

import { createForm } from 'final-form'

// Create Form
const form = createForm({
  initialValues,
  onSubmit, // required
  validate
})

// Subscribe to form state updates
const unsubscribe = form.subscribe(
  formState => {
    // Update UI
  },
  { // FormSubscription: the list of values you want to be updated about
    dirty: true,
    valid: true,
    values: true
  }
})

// Subscribe to field state updates
const unregisterField = form.registerField(
  'username',
  fieldState => {
    // Update field UI
    const { blur, change, focus, ...rest } = fieldState
    // In addition to the values you subscribe to, field state also
    // includes functions that your inputs need to update their state.
  },
  { // FieldSubscription: the list of values you want to be updated about
    active: true,
    dirty: true,
    touched: true,
    valid: true,
    value: true
  }
)

// Submit
form.submit() // only submits if all validation passes

Examples

Vanilla JS Example

You don't need any javascript framework to use 🏁 Final Form's powerful subscription-based form state management. You can attach it directly to the DOM inputs.

Simple React Example

Demonstrates how 🏁 Final Form can be used inside a React component to manage form state. It also shows just how much 🏁 React Final Form does for you out of the box.

For more examples using React, see 🏁 React Final Form Examples.

Official Mutators

Mutators are functions that can be provided to 🏁 Final Form that are allowed to mutate any part of the form state. You provide an object of mutators when you call createForm(), and then they are exposed (bound to the form state) on the form instance you get back, under form.mutators.whatever(). A mutator function is given: the arguments it was called with, the form state, and a collection of utility functions, like getIn and setIn to read and mutate arbitrarily deep values, as well as changeValue, which updates a field value in the form state. They can mutate the state however they wish, and then the form and field subscribers that need to be notified will be notified. Read more about Mutators.

🏁 Final Form Arrays

Helps managing array structures in form data.

🏁 Final Form Set Field Data

Sets arbitrary data for fields.

🏁 Final Form Set Field Touched

Allows control over the touched flags for fields.

Libraries

🏁 React Final Form

A form state management system for React that uses 🏁 Final Form under the hood.

Vue Final Form

A form state management system for Vue that uses 🏁 Final Form under the hood.

Web Components Bindings

CorpusculeJS provides a way to manage form state with 🏁 Final Form using Web Components.

Frontier Forms

Opinionated way to create forms in React. Data-driven forms that let you focus on what matters: your application. Provide a GraphQL mutation and <Frontier/> will do the rest for you.

Define Form and React Define Form

Define Form offers alternative typescript bindings for 🏁 Final Form. The key difference is that the form data is now a strongly typed object, rather than an any. This makes the initialValues config option required.

🏁 Final Form Focus 🧐

A "decorator" that will attempt to apply focus to the first field with an error upon an attempted form submission.

🏁 React Final Form HTML5 Validation

A swap-in replacement for 🏁 React Final Form's <Field> component to provide HTML5 Validation.

🏁 React Final Form Listeners

A collection of useful components for listening to fields in a 🏁 React Final Form.

🏁 Final Form Submit Listener 🧐

A "decorator" that will listen for events around attempted, successful, or failed submissions and fire callbacks you provide.

Field Names

Field names are strings that allow dot-and-bracket syntax, allowing you to create arbitrarily deeply nested fields. There are four main things you need to understand about how field names are used to read and write the form values in 🏁 Final Form.

. and [ are treated the same.
] is ignored.
Number keys will result in array structures. Why?
Setting undefined to a field value deletes any empty object – but not array! – structures. Why?

It is very similar to Lodash's _.set(), except that empty structures are removed. Let's look at some examples:

Field Name	Initial Structure	Setting Value	Result
`bar`	`{}`	`'foo'`	`{ bar: 'foo' }`
`bar.frog`	`{}`	`'foo'`	`{ bar: { frog: 'foo' } }`
`bar[0]`	`{}`	`'foo'`	`{ bar: [ 'foo' ] }`
`bar.0`	`{}`	`'foo'`	`{ bar: [ 'foo' ] }`
`bar[1]`	`{}`	`'foo'`	`{ bar: [ null, 'foo' ] }`
`bar[0].frog`	`{}`	`'foo'`	`{ bar: [ { frog: 'foo' } ] }`
`bar`	`{ bar: 'foo' }`	`undefined`	`{ }`
`bar.frog`	`{ bar: { frog: 'foo' }, other: 42 }`	`undefined`	`{ other: 42 }`
`bar.frog[0]`	`{ bar: { frog: [ 'foo' ] } }`	`undefined`	`{ bar: { frog: [ null ] } }`

Here is a sandbox that you can play around with to get a better understanding of how it works.

API

The following can be imported from final-form.

`createForm: (config: Config) => FormApi`

Creates a form instance. It takes a Config and returns a FormApi.

`fieldSubscriptionItems: string[]`

An à la carte list of all the possible things you can subscribe to for a field. Useful for subscribing to everything.

`formSubscriptionItems: string[]`

An à la carte list of all the possible things you can subscribe to for a form. Useful for subscribing to everything.

`ARRAY_ERROR: string`

A special string key used to return an error for an array of fields.

`FORM_ERROR: string`

A special string key used to return a whole-form error inside error objects returned from validation or submission.

`getIn(state: Object, complexKey: string): any`

`setIn(state: Object, key: string, value: any): Object`

`version: string`

The current used version of 🏁 Final Form.

Types

`Config`

`debug?: DebugFunction`

`destroyOnUnregister?: boolean`

If true, the value of a field will be destroyed when that field is unregistered. Defaults to false. Can be useful when creating dynamic forms where only form values displayed need be submitted.

`keepDirtyOnReinitialize?: boolean`

If true, only pristine values will be overwritten when initialize(newValues) is called. This can be useful for allowing a user to continue to edit a record while the record is being saved asynchronously, and the form is reinitialized to the saved values when the save is successful. Defaults to false.

`initialValues?: Object`

The initial values of your form. These will also be used to compare against the current values to calculate pristine and dirty.

`mutators?: { [string]: Mutator }`

Optional named mutation functions.

`onSubmit: (values: Object, form: FormApi, callback: ?(errors: ?Object) => void) => ?Object | Promise<?Object> | void`

Function to call when the form is submitted. There are three possible ways to write an onSubmit function:

Synchronously: returns undefined on success, or an Object of submission errors on failure
Asynchronously with a callback: returns undefined, calls callback() with no arguments on success, or with an Object of submission errors on failure.
Asynchronously with a Promise: returns a Promise<?Object> that resolves with no value on success or resolves with an Object of submission errors on failure. The reason it resolves with errors is to leave rejection for when there is a server or communications error.

Submission errors must be in the same shape as the values of the form. You may return a generic error for the whole form (e.g. 'Login Failed') using the special FORM_ERROR string key.

`validate?: (values: Object) => Object | Promise<Object>`

A whole-record validation function that takes all the values of the form and returns any validation errors. There are three possible ways to write a validate function:

Synchronously: returns {} or undefined when the values are valid, or an Object of validation errors when the values are invalid.
Asynchronously with a Promise: returns a Promise<?Object> that resolves with no value on success or resolves with an Object of validation errors on failure. The reason it resolves with errors is to leave rejection for when there is a server or communications error.

Validation errors must be in the same shape as the values of the form. You may return a generic error for the whole form using the special FORM_ERROR string key.

`validateOnBlur?: boolean`

If true, validation will happen on blur. If false, validation will happen on change. Defaults to false.

`DebugFunction: (state: FormState, fieldStates: { [string]: FieldState }) => void`

An optional callback for debugging that receives the form state and the states of all the fields. It's called on every state change. A typical thing to pass in might be console.log.

`Decorator: (form: FormApi) => Unsubscribe`

A function that decorates a form by subscribing to it and making changes as the form state changes, and returns an Unsubscribe function to detach itself from the form. e.g. 🏁 Final Form Calculate.

`FieldConfig`

`afterSubmit?: () => void`

A callback to notify fields after submission has completed successfully.

`beforeSubmit?: () => void | false`

A function to call just before calling onSubmit. If beforeSubmit returns false, the submission will be aborted. If one of your fields returns false on beforeSubmit, other fields may not have their beforeSubmit called, as the submission is aborted on the first one that returns false.

`defaultValue?: any`

⚠️ You probably want initialValue! ⚠️

The value of the field upon creation. This value is only needed if you want your field be dirty upon creation (i.e. for its value to be different from its initial value).

`getValidator?: () => (value: ?any, allValues: Object, meta: FieldState) => ?any | ?Promise<any>`

A callback that will return a field-level validation function to validate a single field value. The validation function should return an error if the value is not valid, or undefined if the value is valid.

`initialValue?: any`

The initial value for the field. This value will be used to calculate dirty and pristine by comparing it to the current value of the field. If you want field to be dirty upon creation, you can set one value with initialValue and set the value of the field with defaultValue.

The value given here will override any initialValues given to the entire form.

`isEqual?: (a: any, b: any) => boolean`

A function to determine if two values are equal. Defaults to ===.

`validateFields?: string[]`

An array of field names to validate when this field changes. If undefined, every field will be validated when this one changes; if [], only this field will have its field-level validation function called when it changes; if other field names are specified, those fields and this one will be validated when this field changes.

`FieldState`

FieldState is an object containing:

`active?: boolean`

Whether or not the field currently has focus.

`blur: () => void`

A function to blur the field (mark it as inactive).

`change: (value: any) => void`

A function to change the value of the field.

`data?: Object`

A place for arbitrary values to be placed by mutators.

`dirty?: boolean`

true when the value of the field is not equal to the initial value (using the isEqual comparator provided at field registration), false if the values are equal.

`dirtySinceLastSubmit?: boolean`

true when the value of the field is not equal to the value last submitted (using the isEqual comparator provided at field registration), false if the values are equal.

`error?: any`

The current validation error for this field.

`focus: () => void`

A function to focus the field (mark it as active).

`initial?: any`

The initial value of the field. undefined if it was never initialized.

`invalid?: boolean`

true if the field has a validation error or a submission error. false otherwise.

`length?: number`

The length of the array if the value is an array. undefined otherwise.

`modified?: boolean`

true if this field's value has ever been changed. false otherwise. Once true, it will remain true for the lifetime of the field, or until the form is reset.

`name: string`

The name of the field.

`pristine?: boolean`

true if the current value is === to the initial value, false if the values are !==.

`submitError?: any`

The submission error for this field.

`submitFailed?: boolean`

true if a form submission has been tried and failed. false otherwise.

`submitSucceeded?: boolean`

true if the form has been successfully submitted. false otherwise.

`submitting?: boolean`

true if the form is currently being submitted asynchronously. false otherwise.

`touched?: boolean`

true if this field has ever gained and lost focus. false otherwise. Useful for knowing when to display error messages.

`valid?: boolean`

true if this field has no validation or submission errors. false otherwise.

`value?: any`

The value of the field.

`visited?: boolean`

true if this field has ever gained focus.

`FieldSubscriber: (state: FieldState) => void`

`FieldSubscription: { [string]: boolean }`

FieldSubscription is an object containing the following:

`active?: boolean`

When true the FieldSubscriber will be notified of changes to the active value in FieldState.

`data?: boolean`

When true the FieldSubscriber will be notified of changes to the data value in FieldState.

`dirty?: boolean`

When true the FieldSubscriber will be notified of changes to the dirty value in FieldState.

`dirtySinceLastSubmit?: boolean`

When true the FieldSubscriber will be notified of changes to the dirtySinceLastSubmit value in FieldState.

`error?: boolean`

When true the FieldSubscriber will be notified of changes to the error value in FieldState.

`initial?: boolean`

When true the FieldSubscriber will be notified of changes to the initial value in FieldState.

`invalid?: boolean`

When true the FieldSubscriber will be notified of changes to the invalid value in FieldState.

`length?: boolean`

When true the FieldSubscriber will be notified of changes to the length value in FieldState.

`modified?: boolean`

When true the FieldSubscriber will be notified of changes to the modified value in FieldState.

`pristine?: boolean`

When true the FieldSubscriber will be notified of changes to the pristine value in FieldState.

`submitError?: boolean`

When true the FieldSubscriber will be notified of changes to the submitError value in FieldState.

`submitFailed?: boolean`

When true the FieldSubscriber will be notified of changes to the submitFailed value in FieldState.

`submitSucceeded?: boolean`

When true the FieldSubscriber will be notified of changes to the submitSucceeded value in FieldState.

`submitting?: boolean`

When true the FieldSubscriber will be notified of changes to the submitting value in FieldState.

`touched?: boolean`

When true the FieldSubscriber will be notified of changes to the touched value in FieldState.

`valid?: boolean`

When true the FieldSubscriber will be notified of changes to the valid value in FieldState.

`validating?: boolean`

When true the FieldSubscriber will be notified of changes to the validating value in FieldState.

`value?: boolean`

When true the FieldSubscriber will be notified of changes to the value value in FieldState.

`visited?: boolean`

When true the FieldSubscriber will be notified of changes to the visited value in FieldState.

`FormApi`

`batch: (fn: () => void) => void)`

Allows batch updates by silencing notifications while the fn is running. Example:

form.batch(() => {
  form.change('firstName', 'Erik') // listeners not notified
  form.change('lastName', 'Rasmussen') // listeners not notified
}) // NOW all listeners notified

`blur: (name: string) => void`

Blurs (marks inactive) the given field.

`change: (name: string, value: ?any) => void`

Changes the value of the given field.

`destroyOnUnregister: boolean`

A read/write property to get and set the destroyOnUnregister config setting.

`focus: (name: string) => void`

Focuses (marks active) the given field.

`getFieldState: (field: string) => ?FieldState`

Returns the state of a specific field as it was last reported to its listeners, or undefined if the field has not been registered.

`getRegisteredFields: () => string[]`

Returns a list of all the currently registered fields.

`getState: () => FormState`

A way to request the current state of the form without subscribing.

`initialize: (data: Object | ((values: Object) => Object)) => void`

Initializes the form to the values provided. All the values will be set to these values, and dirty and pristine will be calculated by performing a shallow-equals between the current values and the values last initialized with. The form will be pristine after this call.

`isValidationPaused: () => boolean`

Returns true if validation is currently paused, false otherwise.

`mutators: ?{ [string]: Function }`

The state-bound versions of the mutators provided to Config.

`pauseValidation: () => void`

If called, validation will be paused until resumeValidation() is called.

`registerField: RegisterField`

Registers a new field and subscribes to changes to it. The subscriber will only be called when the values specified in subscription change. More than one subscriber can subscribe to the same field.

This is also where you may provide an optional field-level validation function that should return undefined if the value is valid, or an error. It can optionally return a Promise that resolves (not rejects) to undefined or an error.

`reset: (initialValues: ?Object) => void`

Resets the values back to the initial values the form was initialized with. Or empties all the values if the form was not initialized. If you provide initialValues they will be used as the new initial values.

Note that if you are calling reset() and not specify new initial values, you must call it with no arguments. Be careful to avoid things like promise.catch(reset) or onChange={form.reset} in React, as they will get arguments passed to them and reinitialize your form.

`resumeValidation: () => void`

Resumes validation paused by pauseValidation(). If validation was blocked while it was paused, validation will be run.

`submit: () => ?Promise<?Object>`

Submits the form if there are currently no validation errors. It may return undefined or a Promise depending on the nature of the onSubmit configuration value given to the form when it was created.

`subscribe: (subscriber: FormSubscriber, subscription: FormSubscription) => Unsubscribe`

Subscribes to changes to the form. The subscriber will only be called when values specified in subscription change. A form can have many subscribers.

`FormState`

`active?: string`

The name of the currently active field. undefined if none are active.

`dirty?: boolean`

true if the form values are different from the values it was initialized with. false otherwise. Comparison is done with shallow-equals.

`dirtyFields?: { [string]: boolean }`

An object full of booleans, with a value of true for each dirty field. Pristine fields will not appear in this object. Note that this is a flat object, so if your field name is addresses.shipping.street, the dirty value for that field will be available under dirty['addresses.shipping.street'].

`dirtySinceLastSubmit?: boolean`

true if the form values are different from the values it was last submitted with. false otherwise. Comparison is done with shallow-equals.

`error?: any`

The whole-form error returned by a validation function under the FORM_ERROR key.

`errors?: Object`

An object containing all the current validation errors. The shape will match the shape of the form's values.

`hasSubmitErrors?: boolean`

true when the form currently has submit errors. Useful for distinguishing why invalid is true.

`hasValidationErrors?: boolean`

true when the form currently has validation errors. Useful for distinguishing why invalid is true. For example, if your form is invalid because of a submit error, you might also want to disable the submit button if user's changes to fix the submit errors causes the form to have sync validation errors.

`initialValues?: Object`

The values the form was initialized with. undefined if the form was never initialized.

`invalid?: boolean`

true if any of the fields or the form has a validation or submission error. false otherwise. Note that a form can be invalid even if the errors do not belong to any currently registered fields.

`modified?: { [string]: boolean }`

An object full of booleans, with a boolean value for each field name denoting whether that field is modified or not. Note that this is a flat object, so if your field name is addresses.shipping.street, the modified value for that field will be available under modified['addresses.shipping.street'].

`pristine?: boolean`

true if the form values are the same as the initial values. false otherwise. Comparison is done with shallow-equals.

`submitError?: any`

The whole-form submission error returned by onSubmit under the FORM_ERROR key.

`submitErrors?: Object`

An object containing all the current submission errors. The shape will match the shape of the form's values.

`submitFailed?: boolean`

true if the form was submitted, but the submission failed with submission errors. false otherwise.

`submitSucceeded?: boolean`

true if the form was successfully submitted. false otherwise.

`submitting?: boolean`

true if the form is currently being submitted asynchronously. false otherwise.

`touched?: { [string]: boolean }`

An object full of booleans, with a boolean value for each field name denoting whether that field is touched or not. Note that this is a flat object, so if your field name is addresses.shipping.street, the touched value for that field will be available under touched['addresses.shipping.street'].

`valid?: boolean`

true if neither the form nor any of its fields has a validation or submission error. false otherwise. Note that a form can be invalid even if the errors do not belong to any currently registered fields.

`validating?: boolean`

true if the form is currently being validated asynchronously. false otherwise.

`values?: Object`

The current values of the form.

`visited?: { [string]: boolean }`

An object full of booleans, with a boolean value for each field name denoting whether that field is visited or not. Note that this is a flat object, so if your field name is addresses.shipping.street, the visited value for that field will be available under visited['addresses.shipping.street'].

`FormSubscriber: (state: FormState) => void`

`FormSubscription: { [string]: boolean }`

FormSubscription is an object containing the following:

`active?: boolean`

When true the FormSubscriber will be notified of changes to the active value in FormState.

`dirty?: boolean`

When true the FormSubscriber will be notified of changes to the dirty value in FormState.

`dirtyFields?: boolean`

When true the FormSubscriber will be notified of changes to the dirtyFields value in FormState.

`dirtySinceLastSubmit?: boolean`

When true the FormSubscriber will be notified of changes to the dirtySinceLastSubmit value in FormState.

`error?: boolean`

When true the FormSubscriber will be notified of changes to the error value in FormState.

`errors?: boolean`

When true the FormSubscriber will be notified of changes to the errors value in FormState.

`hasSubmitErrors?: boolean`

When true the FormSubscriber will be notified of changes to the hasSubmitErrors value in FormState.

`hasValidationErrors?: boolean`

When true the FormSubscriber will be notified of changes to the hasValidationErrors value in FormState.

`initialValues?: boolean`

When true the FormSubscriber will be notified of changes to the initialValues value in FormState.

`invalid?: boolean`

When true the FormSubscriber will be notified of changes to the invalid value in FormState.

`modified?: boolean`

When true the FormSubscriber will be notified of changes to the modified value in FormState.

`pristine?: boolean`

When true the FormSubscriber will be notified of changes to the pristine value in FormState.

`setConfig: (name: string, value: any) => void`

Allows mutating the values on the original Config.

`submitError?: boolean`

When true the FormSubscriber will be notified of changes to the submitError value in FormState.

`submitErrors?: boolean`

When true the FormSubscriber will be notified of changes to the submitErrors value in FormState.

`submitFailed?: boolean`

When true the FormSubscriber will be notified of changes to the submitFailed value in FormState.

`submitSucceeded?: boolean`

When true the FormSubscriber will be notified of changes to the submitSucceeded value in FormState.

`submitting?: boolean`

When true the FormSubscriber will be notified of changes to the submitting value in FormState.

`touched?: boolean`

When true the FormSubscriber will be notified of changes to the touched value in FormState.

`valid?: boolean`

When true the FormSubscriber will be notified of changes to the valid value in FormState.

`validating?: boolean`

When true the FormSubscriber will be notified of changes to the validating value in FormState.

`values?: boolean`

When true the FormSubscriber will be notified of changes to the values value in FormState.

`visited?: boolean`

When true the FormSubscriber will be notified of changes to the visited value in FormState.

`InternalFieldState`

Very similar to the published FieldState.

`active: boolean`

Whether or not the field currently has focus.

`blur: () => void`

A function to blur the field (mark it as inactive).

`change: (value: any) => void`

A function to change the value of the field.

`data: Object`

A place for arbitrary values to be placed by mutators.

`focus: () => void`

A function to focus the field (mark it as active).

`isEqual: (a: any, b: any) => boolean`

A function to determine if two values are equal. Used to calculate pristine/dirty.

`modified: boolean`

true if this field's value has ever changed. false otherwise. Useful for knowing when to display error messages. Once true, it will remain true for the lifetime of the field, or until the form is reset.

`name: string`

The name of the field.

`touched: boolean`

true if this field has ever gained and lost focus. false otherwise. Useful for knowing when to display error messages.

`validateFields: ?(string[])`

Fields to validate when this field value changes.

`validators: { [number]: (value: ?any, allValues: Object, meta: FieldState) => ?any | Promise<?any> } }`

Field-level validators for each field that is registered.

`valid: boolean`

true if this field has no validation or submission errors. false otherwise.

`validating: boolean`

true if this field is currently waiting on its asynchronous field-level validation function to resolve. false otherwise.

`visited: boolean`

true if this field has ever gained focus.

`InternalFormState`

Very similar to the published FormState, with a few minor differences.

`active?: string`

The name of the currently active field. undefined if none are active.

`dirtySinceLastSubmit: boolean`

true if the form values have changed since the last time the form was submitted, false otherwise.

`error?: any`

The whole-form error returned by a validation function under the FORM_ERROR key.

`errors: Object`

An object containing all the current validation errors. The shape will match the shape of the form's values.

`initialValues?: Object`

The values the form was initialized with. undefined if the form was never initialized.

`lastSubmittedValues?: Object`

The values last submitted. Used to calculate dirtySinceLastSubmit.

`pristine: boolean`

true if the form values are the same as the initial values. false otherwise. Comparison is done with shallow-equals.

`submitError: any`

The whole-form submission error returned by onSubmit under the FORM_ERROR key.

`submitErrors?: Object`

An object containing all the current submission errors. The shape will match the shape of the form's values.

`submitFailed: boolean`

true if the form was submitted, but the submission failed with submission errors. false otherwise.

`submitSucceeded: boolean`

true if the form was successfully submitted. false otherwise.

`submitting: boolean`

true if the form is currently being submitted asynchronously. false otherwise.

`valid: boolean`

`validating: number`

The number of asynchronous validators currently running.

`values: Object`

The current values of the form.

`MutableState`

MutableState is an object containing the following:

`formState: InternalFormState`

The InternalFormState.

`fields: { [string]: InternalFieldState }`

An object of InternalFieldStates.

`fieldSubscribers: { [string]: Subscribers<FieldState> }`

An object of field subscribers.

`lastFormState: ?InternalFormState`

The last form state sent to form subscribers.

`Mutator: (args: any[], state: MutableState, tools: Tools) => any`

A mutator function that takes some arguments, the internal form MutableState, and some Tools and optionally modifies the form state.

`RegisterField: (name: string, subscriber: FieldSubscriber, subscription: FieldSubscription, config?: FieldConfig) => Unsubscribe`

Takes a name, and a FieldSubscriber, FieldSubscription, and a FieldConfig and registers a field subscription. Learn more about how Field Names.

`Tools`

An object containing:

`Tools.changeValue: (state: MutableState, name: string, mutate: (value: any) => any) => void`

A utility function to modify a single field value in form state. mutate() takes the old value and returns the new value.

`Tools.getIn: (state: Object, complexKey: string) => any`

A utility function to get any arbitrarily deep value from an object using dot-and-bracket syntax (e.g. some.deep.values[3].whatever).

`Tools.renameField: (state: MutableState, from: string, to: string) => any) => void`

A utility function to rename a field, copying over its value and field subscribers. Advanced usage only.

`Tools.setIn: (state: Object, key: string, value: any) => Object`

A utility function to set any arbitrarily deep value inside an object using dot-and-bracket syntax (e.g. some.deep.values[3].whatever). Note: it does not mutate the object, but returns a new object.

`Tools.shallowEqual: (a: any, b: any) => boolean`

A utility function to compare the keys of two objects. Returns true if the objects have the same keys and the values are ===, false otherwise.

`Unsubscribe : () => void`

Unsubscribes a listener.

Contributors

This project exists thanks to all the people who contribute. [Contribute].

Backers

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final-form

What is final-form?

What are final-form's main functionalities?

Other packages similar to final-form

formik

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🏁 Final Form

💬 Give Feedback on Final Form 💬

Installation

Zero Dependencies

Getting Started

Table of Contents

Examples

Official Mutators

Libraries

Define Form and React Define Form

Field Names

API

createForm: (config: Config) => FormApi

fieldSubscriptionItems: string[]

formSubscriptionItems: string[]

ARRAY_ERROR: string

FORM_ERROR: string

getIn(state: Object, complexKey: string): any

setIn(state: Object, key: string, value: any): Object

version: string

Types

Config

debug?: DebugFunction

destroyOnUnregister?: boolean

keepDirtyOnReinitialize?: boolean

initialValues?: Object

mutators?: { [string]: Mutator }

onSubmit: (values: Object, form: FormApi, callback: ?(errors: ?Object) => void) => ?Object | Promise<?Object> | void

validate?: (values: Object) => Object | Promise<Object>

validateOnBlur?: boolean

DebugFunction: (state: FormState, fieldStates: { [string]: FieldState }) => void

Decorator: (form: FormApi) => Unsubscribe

FieldConfig

afterSubmit?: () => void

beforeSubmit?: () => void | false

defaultValue?: any

getValidator?: () => (value: ?any, allValues: Object, meta: FieldState) => ?any | ?Promise<any>

initialValue?: any

isEqual?: (a: any, b: any) => boolean

validateFields?: string[]

FieldState

active?: boolean

blur: () => void

change: (value: any) => void

data?: Object

dirty?: boolean

dirtySinceLastSubmit?: boolean

error?: any

focus: () => void

initial?: any

invalid?: boolean

length?: number

modified?: boolean

name: string

pristine?: boolean

submitError?: any

submitFailed?: boolean

submitSucceeded?: boolean

submitting?: boolean

touched?: boolean

valid?: boolean

value?: any

visited?: boolean

FieldSubscriber: (state: FieldState) => void

FieldSubscription: { [string]: boolean }

active?: boolean

data?: boolean

dirty?: boolean

dirtySinceLastSubmit?: boolean

error?: boolean

initial?: boolean

invalid?: boolean

length?: boolean

`createForm: (config: Config) => FormApi`

`fieldSubscriptionItems: string[]`

`formSubscriptionItems: string[]`

`ARRAY_ERROR: string`

`FORM_ERROR: string`

`getIn(state: Object, complexKey: string): any`

`setIn(state: Object, key: string, value: any): Object`

`version: string`

`Config`

`debug?: DebugFunction`

`destroyOnUnregister?: boolean`

`keepDirtyOnReinitialize?: boolean`

`initialValues?: Object`

`mutators?: { [string]: Mutator }`

`onSubmit: (values: Object, form: FormApi, callback: ?(errors: ?Object) => void) => ?Object | Promise<?Object> | void`

`validate?: (values: Object) => Object | Promise<Object>`

`validateOnBlur?: boolean`

`DebugFunction: (state: FormState, fieldStates: { [string]: FieldState }) => void`

`Decorator: (form: FormApi) => Unsubscribe`

`FieldConfig`

`afterSubmit?: () => void`

`beforeSubmit?: () => void | false`

`defaultValue?: any`

`getValidator?: () => (value: ?any, allValues: Object, meta: FieldState) => ?any | ?Promise<any>`

`initialValue?: any`

`isEqual?: (a: any, b: any) => boolean`

`validateFields?: string[]`

`FieldState`

`active?: boolean`

`blur: () => void`

`change: (value: any) => void`

`data?: Object`

`dirty?: boolean`

`dirtySinceLastSubmit?: boolean`

`error?: any`

`focus: () => void`

`initial?: any`

`invalid?: boolean`

`length?: number`

`modified?: boolean`

`name: string`

`pristine?: boolean`

`submitError?: any`

`submitFailed?: boolean`

`submitSucceeded?: boolean`

`submitting?: boolean`

`touched?: boolean`

`valid?: boolean`

`value?: any`

`visited?: boolean`

`FieldSubscriber: (state: FieldState) => void`

`FieldSubscription: { [string]: boolean }`

`active?: boolean`

`data?: boolean`

`dirty?: boolean`

`dirtySinceLastSubmit?: boolean`

`error?: boolean`

`initial?: boolean`

`invalid?: boolean`

`length?: boolean`

`modified?: boolean`

`pristine?: boolean`

`submitError?: boolean`

`submitFailed?: boolean`

`submitSucceeded?: boolean`

`submitting?: boolean`

`touched?: boolean`

`valid?: boolean`

`validating?: boolean`

`value?: boolean`

`visited?: boolean`

`FormApi`

`batch: (fn: () => void) => void)`

`blur: (name: string) => void`

`change: (name: string, value: ?any) => void`

`destroyOnUnregister: boolean`

`focus: (name: string) => void`

`getFieldState: (field: string) => ?FieldState`

`getRegisteredFields: () => string[]`

`getState: () => FormState`