redux-form

What is redux-form?

redux-form is a library that allows you to manage form state in Redux. It provides a way to keep form state in a Redux store, making it easier to manage complex forms and their validation, submission, and other behaviors.

What are redux-form's main functionalities?

Form Creation

This code demonstrates how to create a simple form using redux-form. The `Field` component is used to define form fields, and the `reduxForm` higher-order component is used to connect the form to Redux.

import React from 'react';
import { Field, reduxForm } from 'redux-form';

let SimpleForm = props => {
  const { handleSubmit } = props;
  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label htmlFor="firstName">First Name</label>
        <Field name="firstName" component="input" type="text" />
      </div>
      <button type="submit">Submit</button>
    </form>
  );
};

SimpleForm = reduxForm({
  form: 'simple'
})(SimpleForm);

export default SimpleForm;

Form Validation

This code demonstrates how to add validation to a form using redux-form. The `validate` function checks for errors and returns an object with error messages, which are then used by redux-form to display validation errors.

import React from 'react';
import { Field, reduxForm } from 'redux-form';

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

let ValidatedForm = props => {
  const { handleSubmit } = props;
  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label htmlFor="firstName">First Name</label>
        <Field name="firstName" component="input" type="text" />
      </div>
      <button type="submit">Submit</button>
    </form>
  );
};

ValidatedForm = reduxForm({
  form: 'validated',
  validate
})(ValidatedForm);

export default ValidatedForm;

Form Submission

This code demonstrates how to handle form submission using redux-form. The `handleSubmit` function is passed a `submit` function that processes the form data.

import React from 'react';
import { Field, reduxForm } from 'redux-form';

const submit = values => {
  console.log('Form data:', values);
};

let SubmitForm = props => {
  const { handleSubmit } = props;
  return (
    <form onSubmit={handleSubmit(submit)}>
      <div>
        <label htmlFor="firstName">First Name</label>
        <Field name="firstName" component="input" type="text" />
      </div>
      <button type="submit">Submit</button>
    </form>
  );
};

SubmitForm = reduxForm({
  form: 'submit'
})(SubmitForm);

export default SubmitForm;

Other packages similar to redux-form

formik

Formik is a popular form library for React that provides a simpler API compared to redux-form. It focuses on reducing boilerplate and improving performance by not relying on Redux for form state management. Formik is often preferred for its ease of use and flexibility.

react-hook-form

React Hook Form is a library that uses React hooks to manage form state and validation. It is known for its minimal re-renders and high performance. Unlike redux-form, it does not require Redux and is often chosen for its simplicity and performance benefits.

final-form

Final Form is a framework-agnostic form state management library that can be used with React through the react-final-form package. It offers similar functionality to redux-form but is designed to be more lightweight and flexible, without the need for Redux.

README

#redux-form

redux-form works with React Redux to enable an html form in React to use Redux to store all of its state.

Table of Contents

• Installation
• Release Notes
• Benefits - Why use this library?
  • Unidirectional Data Flow
  • Redux Dev Tools
  • Stateless Components
• Implementation Guide <-------------- Start here!
  • A Simple Form Component
  • ES7 Decorator Sugar - :warning: Experimental! :warning:
  • Synchronous Validation - Client Side
  • Asynchronous Validation - Server Side
  • Submitting Your Form
  • Responding to Other Actions
  • Normalizing Form Data
  • Editing Multiple Records
  • Calculating props from Form Data
  • Advanced Usage
    • Doing the connect()ing Yourself
      • Binding Action Creators
• API
  • connectReduxForm(config)
  • reduxForm(config)
  • reducer
  • reducer.plugin(Object<String, Function>)
  • reducer.normalize(Object<String, Function>)
  • props passed into your decorated component - props provided by redux-form
  • props you can pass into your decorated component - extra functionality!
  • Action Creators - Advanced
• Working Demo

---

Installation

npm install --save redux-form

Release Notes

This project follows SemVer and each release is posted on the Release Notes page.

Benefits

Why would anyone want to do this, you ask? React a perfectly good way of keeping state in each component! The reasons are threefold.

Unidirectional Data Flow

For the same reason that React and Flux is superior to Angular's bidirectional data binding. Tracking down bugs is much simpler when the data all flows through one dispatcher.

Redux Dev Tools

When used in conjunction with Redux Dev Tools, you can fast forward and rewind through your form data entry to better find bugs.

Stateless Components

By removing the state from your form components, you inherently make them easier to understand, test, and debug. The React philosophy is to always try to use props instead of state when possible.

Implementation Guide

STEP 1: The first thing that you have to do is to give the redux-form reducer to Redux. You will only have to do this once, no matter how many form components your app uses.

import { createStore, combineReducers } from 'redux';
import { reducer as formReducer } from 'redux-form';
const reducers = {
  // ... your other reducers here ...
  form: formReducer   // it is recommended that you use the key 'form'
}
const reducer = combineReducers(reducers);
const store = createStore(reducer);

STEP 2: Wrap your form component with connectReduxForm(). connectReduxForm() wraps your form component in a Higher Order Component that connects to the Redux store and provides functions, as props to your component, for your form elements to use for sending onChange and onBlur events, as well as a function to handle synchronous validation onSubmit. Let's look at a simple example.

A Simple Form Component

You will need to wrap your form component with redux-form's connectReduxForm() function.

IMPORTANT: If you are using react-form with react-native, you will need to use reduxForm() instead of connectReduxForm(), at least until React 0.14 is released.

import React, {Component, PropTypes} from 'react';
import {connectReduxForm} from 'redux-form';
import validateContact from './validateContact';

class ContactForm extends Component {
  static propTypes = {
    fields: PropTypes.object.isRequired,
    handleSubmit: PropTypes.func.isRequired
  }
  
  render() {
    const { fields: {name, address, phone}, handleSubmit } = this.props;
    return (
      <form onSubmit={handleSubmit}>
        <label>Name</label>
        <input type="text" {...name}/>     // will pass value, onBlur and onChange
        {name.error && name.touched ? <div>{name.error}</div>}
        
        <label>Address</label>
        <input type="text" {...address}/>  // will pass value, onBlur and onChange
        {address.error && address.touched ? <div>{address.error}</div>}
        
        <label>Phone</label>
        <input type="text" {...phone}/>    // will pass value, onBlur and onChange
        {phone.error && phone.touched ? <div>{phone.error}</div>}
        
        <button onClick={handleSubmit}>Submit</button>
      </form>
    );
  }
}

// apply connectReduxForm() and include synchronous validation
ContactForm = connectReduxForm({
  form: 'contact',                      // the name of your form and the key to
                                        // where your form's state will be mounted
  fields: ['name', 'address', 'phone'], // a list of all your fields in your form
  validate: validateContact             // a synchronous validation function
})(ContactForm);

// export the wrapped component
export default ContactForm;

Notice that we're just using vanilla <input> elements there is no state in the ContactForm component. handleSubmit will call the function passed into ContactForm's onSubmit prop, if and only if the synchronous validation passes. See Submitting Your Form.

ES7 Decorator Sugar

Using ES7 decorator proposal, the example above could be written as:

@connectReduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  validate: validateContact
})
export default class ContactForm extends Component {

Much nicer, don't you think?

You can enable it with Babel Stage 1. Note that decorators are experimental, and this syntax might change or be removed later.

Synchronous Validation

You may optionally supply a validation function, which is in the form ({}) => {} and takes in all your data and spits out error messages. Your error messages may be strings or arrays of strings (if your field data is complex). For example:

function validateContact(data) {
  const errors = {};
  if(!data.name) {
    errors.name = 'Required';
  }
  if(data.address && data.address.length > 50) {
    errors.address = 'Must be fewer than 50 characters';
  }
  if(!data.phone) {
    errors.phone = 'Required';
  } else if(!/\d{3}-\d{3}-\d{4}/.test(data.phone)) {
    errors.phone = 'Phone must match the form "999-999-9999"'
  }
  return errors;
}

You get the idea.

Asynchronous Validation

Async validation can be achieved by calling an additional function on the function returned by connectReduxForm() and passing it an asynchronous function that returns a promise that will resolve to validation errors of the format that the synchronous validation function generates. So this...

// apply connectReduxForm() and include synchronous validation
ContactForm = connectReduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  validate: validateContact
})(ContactForm);

...changes to this:

function validateContactAsync(data) {
  return new Promise((resolve, reject) => {
    const errors = {};
    // do async validation
    resolve(errors);
  });
}

// apply connectReduxForm() and include synchronous AND asynchronous validation
ContactForm = connectReduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  validate: validateContact,
  asyncValidate: validateContactAsync
})(ContactForm);

Optionally, if you want asynchronous validation to be triggered when one or more of your form fields is blurred, you may pass those fields to the async() function along with the asynchronous validation function. Like so:

// will only run async validation when 'name' or 'phone' is blurred
ContactForm = connectReduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  validate: validateContact,
  asyncValidate: validateContactAsync,
  asyncBlurFields: ['name', 'phone']
})(ContactForm);

With that call, the asynchronous validation will be called when either name or phone is blurred. Assuming that they have their onBlur={handleBlur('name')} properties properly set up.

NOTE! If you only want asynchronous validation, you may leave out the synchronous validation function. And if you only want it to be run on submit, you may leave out the async blur fields, as well.

ContactForm = connectReduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  asyncValidate: validateContactAsync
})(ContactForm);

Submitting Your Form

The recommended way to submit your form is to create your form component as shown above, using the handleSubmit prop, and then pass an onSubmit prop to your form component.

import React, {Component, PropTypes} from 'react';
import {connect} from 'react-redux';
import {initialize} from 'redux-form';

class ContactPage extends Component {
  static propTypes = {
    dispatch: PropTypes.func.isRequired
  }
  
  handleSubmit(data) {
    console.log('Submission received!', data);
    this.props.dispatch(initialize('contactForm', {})); // clear form
  }
  
  render() {
    return (
      <div>
        <h1>Contact Information</h1>
        
        <ContactForm onSubmit={this.handleSubmit.bind(this)}/>
      </div>
    );
  }
}

export default connect()(ContactPage);  // adds dispatch prop

Or, if you wish to do your submission directly from your decorated form component, you may pass a function to handleSubmit. To abbreviate the example shown above:

class ContactForm extends Component {
  static propTypes = {
    // ...
    handleSubmit: PropTypes.func.isRequired
  }
  
  saveForm(data) {
    // make server call to save the data
  }
  
  render() {
    const {
      // ...
      handleSubmit
    } = this.props;
    return (
      <form onSubmit={handleSubmit(this.saveForm)}> // <--- pass saveForm
        // ...
      </form>
    );
  }
}

Responding to Other Actions

Part of the beauty of the flux architecture is that all the reducers (or "stores", in canonical Flux terminology) receive all the actions, and they can modify their data based on any of them. For example, say you have a login form, and when your login submission fails, you want to clear out the password field. Your login submission is part of another reducer/actions system, but your form can still respond.

Rather than just using the vanilla reducer from redux-form, you can augment it to do other things by calling the plugin() function.

import {reducer as formReducer} from 'redux-form';
import {AUTH_LOGIN_FAIL} from '../actions/actionTypes';

const reducers = {
  // ... your other reducers here ...
  form: formReducer.plugin({
    login: (state, action) => { // <------ 'login' is name of form given to connectReduxForm()
      switch(action.type) {
        case AUTH_LOGIN_FAIL:
          return {
            ...state,
            password: {}        // <----- clear password field
          };
        default:
          return state;
      }
    }
  })
}
const reducer = combineReducers(reducers);
const store = createStore(reducer);

Normalizing Form Data

Let's say that you have a form field that only accepts uppercase letters and another one where you want the value to be formatted in the 999-999-9999 United States phone number format. redux-form gives you a way to normalize your data on every action to the reducer by calling the normalize() function on the default reducer.

import {reducer as formReducer} from 'redux-form';

const reducers = {
  // ... your other reducers here ...
  form: formReducer.normalize({
    contact: {                                           // <--- the form name
      licensePlate: (value, previousValue, allValues) => // <--- field normalizer
        value && value.toUpperCase(),
      phone: (value, previousValue, allValues) => {      // <--- field normalizer
        if (value) {
          const match = value.match(/(\d{3})-?(\d{3})-?(\d{4})/);
          if (match) {
            return `${match[1]}-${match[2]}-${match[3]}`;
          }
        }
        return value;
      }
    }
  })
}
const reducer = combineReducers(reducers);
const store = createStore(reducer);

Editing Multiple Records

Editing multiple records on the same page is trivially easy with redux-form. All you have to do is to pass a unique formKey and initialValues props into your form element. Let's say we want to edit many contacts on the same page.

import React, {Component, PropTypes} from 'react';
import ContactForm from './ContactForm';

export default class ContactsPage extends Component {
  static propTypes = {
    contacts: PropTypes.array.isRequired  // how you pass the data in is up to you
  }
  
  handleSubmit(id, data) {
    // send to server
  }
  
  render() {
    const {contacts} = this.props;
    return (
      <div>
        {contacts.map(function (contact) {
          return <ContactForm
                   key={contact.id}                  // required by react
                   formKey={String(contact.id)}      // required by redux-form
                   initialValues={contact}           // initialize form values
                   onSubmit={this.handleSubmit.bind(this, contact.id)}/>
        })}
      </div>
    );
  }
}

Calculating props from Form Data

You may want to have some calculated props, perhaps using reselect selectors based on the values of the data in your form. You might be tempted to do this in the mapStateToProps given to connect(). This will not work. The reason is that the form contents in the Redux store are lazily initialized, so state.form.contacts.data.name will fail, because state.form.contacts will be undefined until the first form action is dispatched.

The recommended way to accomplish this is to use yet another Higher Order Component decorator, such as map-props, like so:

import mapProps from 'map-props';
...
// FIRST map props
ContactForm = mapProps({
  hasName: props => !!props.name.value
  hasPhone: props => !!props.phone.value
})(ContactForm);

// THEN apply connectReduxForm() and include synchronous validation
ContactForm = connectReduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  validate: validateContact
})(ContactForm);
...

Or, in ES7 land...

@connectReduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  validate: validateContact
})
@mapProps({
  hasName: props => !!props.name.value
  hasPhone: props => !!props.phone.value
})
export default class ContactForm extends Component {

---

Advanced Usage

Doing the connect()ing Yourself

If, for some reason, you cannot mount the redux-form reducer at form in Redux, you may mount it anywhere else and do the connect() call yourself. Rather than wrap your form component with redux-form's connectReduxForm(), you will need to wrap your form component both with React Redux's connect() function and with redux-form's reduxForm() function.

import React, {Component, PropTypes} from 'react';
import {connect} from 'react-redux';
import reduxForm from 'redux-form';
import validateContact from './validateContact';

class ContactForm extends Component {
  //...
}

// apply reduxForm() and include synchronous validation
// note: we're using reduxForm, not connectReduxForm
ContactForm = reduxForm({
  form: 'contact',
  fields: ['name', 'address', 'phone'],
  validate: validateContact
})(ContactForm);

// ------- HERE'S THE IMPORTANT BIT -------
function mapStateToProps(state, ownProps) {
  // this is React Redux API: https://github.com/rackt/react-redux
  // for example, you may use ownProps here to refer to the props passed from parent.
  return {
    form: state.placeWhereYouMountedFormReducer[ownProps.something]
  };
}

// apply connect() to bind it to Redux state
ContactForm = connect(mapStateToProps)(ContactForm);

// export the wrapped component
export default ContactForm;

As you can see, connectReduxForm() is a tiny wrapper over reduxForm() that applies connect() for you.

Binding Action Creators

When doing the connect()ing yourself, if your form component also needs other redux action creators - and you will if you are performing your server submit in your form component - you cannot simply use the default bindActionCreators() from redux, because that will remove dispatch from the props the connect() passes along, and reduxForm() needs dispatch. You will need to also include dispatch in your mapDispatchToProps() function. So change this...

import {bindActionCreators} from `redux`;

...

function mapDispatchToProps(dispatch) {
  return bindActionCreators(actionCreators, dispatch);
}

ContactForm = connect(
  mapStateToProps,
  mapDispatchToProps
)(ContactForm);

...to...

import {bindActionCreators} from `redux`;

...

function mapDispatchToProps(dispatch) {
  return {
    ...bindActionCreators(actionCreators, dispatch),
    dispatch  // <----- passing dispatch, too
  };
}

ContactForm = connect(
  mapStateToProps,
  mapDispatchToProps
)(ContactForm);

---

API

connectReduxForm(config:Object)

-config.form : string [optional]

the name of your form and the key to where your form's state will be mounted, under the redux-form reducer, in the Redux store. If you do not provide this, you must pass it in as a formName prop to your component.

-config.fields : Array<string>

a list of all your fields in your form. This is used for marking all of the fields as touched on submit.

-config.validate : Function [optional]

your synchronous validation function. Defaults to () => ({})

-config.touchOnBlur : boolean [optional]

marks fields to touched when the blur action is fired. Defaults to true

-config.touchOnChange : boolean [optional]

marks fields to touched when the change action is fired. Defaults to false

-config.asyncValidate : Function [optional]

a function that takes all the form data and returns a Promise that will resolve to an object of validation errors in the form { field1: <string>, field2: <string>, valid: <boolean> } just like the synchronous validation function. See Aynchronous Validation for more details.

-config.asyncBlurFields : Array<String> [optional]

field names for which handleBlur should trigger a call to the asyncValidate function. Defaults to [].

---

reduxForm(config:Object)

[NOT RECOMMENDED] reduxForm() has the same API as connectReduxForm() except that you must wrap the component in connect() yourself.

---

reducer

The form reducer. Should be given to mounted to your Redux state at form.

---

reducer.plugin(Object<String, Function>)

Returns a form reducer that will also pass each action through additional reducers specified. The parameter should be an object mapping from formName to a (state, action) => nextState reducer. The state passed to each reducer will only be the slice that pertains to that form. See Responding to Other Actions.

---

reducer.normalize(Object<String, Object<String, Function>>)

Returns a form reducer that will also pass each form value through the normalizing functions provided. The parameter is an object mapping from formName to an object mapping from fieldName to a normalizer function. The normalizer function is given three parameters and expected to return the normalized value of the field. See Normalizing Form Data.

-value : string

The current value of the field

-previousValue : string

The previous value of the field before the current action was dispatched

-allValues : Object<string, string>

All the values of the current form

---

props passed into your decorated component

The props passed into your decorated component by react-form will be:

-asyncValidate : Function

a function that may be called to initiate asynchronous validation if asynchronous validation is enabled

-asyncValidating : boolean

true if the asynchronous validation function has been called but has not yet returned.

-dirty : boolean

true if the form data has changed from its initialized values. Opposite of pristine.

-fields : Object

The form data, in the form { field1: <Object>, field2: <Object> }, where each field Object has the following properties:

---checked : boolean?

An alias for value only when value is a boolean. Provided for convenience of destructuring the whole field object into the props of a form element.

---dirty : boolean

true if the field value has changed from its initialized value. Opposite of pristine.

---error : String?

The error for this field if its value is not passing validation. Both synchronous and asynchronous validation errors will be reported here.

---handleBlur : Function

A function to call when the form field is blurred. It expects to receive the React SyntheticEvent and is meant to be passed to the form element's onBlur prop.

---handleChange : Function

A function to call when the form field is blurred. It expects to receive the React SyntheticEvent and is meant to be passed to the form element's onChange prop.

---invalid : boolean

true if the field value fails validation (has a validation error). Opposite of valid.

---name : String

The name of the field. It will be the same as the key in the fields Object, but useful if bundling up a field to send down to a specialized input component.

---onBlur : Function

An alias for handleBlur. Provided for convenience of destructuring the whole field object into the props of a form element.

---onChange : Function

An alias for handleChange. Provided for convenience of destructuring the whole field object into the props of a form element.

---pristine : boolean

true if the field value is the same as its initialized value. Opposite of dirty.

---touched : boolean

true if the field has been touched.

---valid : boolean

true if the field value passes validation (has no validation errors). Opposite of invalid.

---value: any

The value of this form field. It will be a boolean for checkboxes, and a string for all other input types.

-handleBlur(field:string) : Function

Returns a handleBlur function for the field passed. handleBlur('age') returns fields.age.handleBlur.

-handleChange(field:string) : Function

Returns a handleChange function for the field passed. handleChange('age') returns fields.age.handleChange.

-handleSubmit : Function

a function meant to be passed to <form onSubmit={handleSubmit}> or to <button onClick={handleSubmit}>. It will run validation, both sync and async, and, if the form is valid, it will call this.props.onSubmit(data) with the contents of the form data.

Optionally, you may also pass your onSubmit function to handleSubmit which will take the place of the onSubmit prop. For example: <form onSubmit={handleSubmit(this.save.bind(this))}>

-initializeForm(data:Object) : Function

Initializes the form data to the given values. All dirty and pristine state will be determined by comparing the current data with these initialized values.

-invalid : boolean

true if the form has validation errors. Opposite of valid.

-pristine: boolean

true if the form data is the same as its initialized values. Opposite of dirty.

-resetForm() : Function

Resets all the values in the form to the initialized state, making it pristine again.

-formKey : String

The same formKey prop that was passed in. See Editing Multiple Records.

-submitting : boolean

Whether or not your form is currently submitting. This prop will only work if you have passed an onSubmit function that returns a promise. It will be true until the promise is resolved or rejected.

-touch(...field:string) : Function

Marks the given fields as "touched" to show errors.

-touchAll() : Function

Marks all fields as "touched" to show errors. should be called on form submission.

-untouch(...field:string) : Function

Clears the "touched" flag for the given fields

-untouchAll() : Function

Clears the "touched" flag for the all fields

-valid : boolean

true if the form passes validation (has no validation errors). Opposite of invalid.

-values : Object

All of your values in the form { field1: <string>, field2: <string> }.

---

props you can pass into your decorated component

The props that you can pass into decorated component by react-form will be:

-formKey : String [optional]

a unique key for the subform this component will be editing. See Editing Multiple Records.

-formName : String [optional]

the name of your form and the key to where your form's state will be mounted, under the redux-form reducer, in the Redux store. Will overwrite any config.form value that was passed to connectReduxForm(config).

-initialValues : Object [optional]

the values with which to initialize your form in componentWillMount. Particularly useful when Editing Multiple Records, but can also be used with single-record forms.

-onSubmit : Function [optional]

the function to call with the form data when the handleSubmit is fired from within the form component. If you do not specify it as a prop here, you must pass it as a parameter to handleSubmit inside your form component.

---

Action Creators

redux-form exports all of its internal action creators, allowing you complete control to dispatch any action you wish. However, it is highly recommended that you use the actions passed as props to your component for most of your needs.

-blur(form:String, field:String, value:String)

Saves the value and, if you have touchOnBlur enabled, marks the field as touched.

-change(form:String, field:String, value:String)

Saves the value and, if you have touchOnChange enabled, marks the field as touched.

-initialize(form:String, data:Object)

Sets the initial values in the form with which future data values will be compared to calculate dirty and pristine. The data parameter should only contain String values.

-initializeWithKey(form:String, formKey, data:Object)

Used when editing multiple records with the same form component. See Editing Multiple Records.

-reset(form:String)

Resets the values in the form back to the values past in with the most recent initialize action.

-startAsyncValidation(form:String)

Flips the asyncValidating flag true.

-stopAsyncValidation(form:String, errors:Object)

Flips the asyncValidating flag false and populates asyncErrors.

-touch(form:String, ...fields:String)

Marks all the fields passed in as touched.

-untouch(form:String, ...fields:String)

Resets the 'touched' flag for all the fields passed in.

---

Working Demo

Check out the react-redux-universal-hot-example project to see redux-form in action.

This is an extremely young library, so the API may change. Comments and feedback welcome.