JSPM

#redux-form

@reduxForm is an ES7 decorator to for enabling a form in React to use Redux to store all of its state.

Installation

npm install --save redux-form

Benefits

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

Hot Reloading

When used in conjunction with React Hot Loader, you can modify your components, rebuild your app and immediately see your changes without losing your form data. This may seem trivial, but the minutes of refilling out forms in a develomnet environment really add up.

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.

How it works

When you are adding your reducers to your redux store, add a new one with createFormReducer(]).

import { createStore, combineReducers } from 'redux';
import { createFormReducer } from 'redux-form';
const reducers = {
  // ... your other reducers here ...
  createFormReducer('contacts', ['name', 'address', 'phone'], contactValidation)
}
const reducer = combineReducers(reducers);
const store = createStore(reducer);

Then, on your form component, add the @reduxForm('contacts') decorator.

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

@reduxForm('contacts')
export default class ContactForm extends Component {
  static propTypes = {
    data: PropTypes.object.isRequired,
    errors: PropTypes.object.isRequired,
    handleChange: PropTypes.func.isRequired,
    validate: PropTypes.func.isRequired,
    reset: PropTypes.func.isRequired
  }
  
  render() {
    const {
      data: {name, address, phone},
      errors: {name: nameError, address: addressError, phone: phoneError}
    } = this.props;
    return (
      <form>
        <label>Name</label>
        <input type="text" value={name} onChange={handleChange('name')}/>
        {nameError ? <div>{nameError}</div>}
        
        <label>Address</label>
        <input type="text" value={address} onChange={handleChange('address')}/>
        {addressError ? <div>{addressError}</div>}
        
        <label>Phone</label>
        <input type="text" value={phone} onChange={handleChange('phone')}/>
        {phoneError ? <div>{phoneError}</div>}
      </form>
    );
  }
}

Notice that we're just using vanilla <input> elements there is no state in the ContactForm component. I have left handling onSubmit as an excercise for the reader. Hint: your data is in this.props.data.

Validation

You will need to supply your own validation function, which is in the form ({}) => {} and takes in all your data and spits out error messages. For example:

function contactValidation(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.

API

Each form has a sliceName. That's the key in the Redux store tree where the data will be mounted.

createFormReducer(sliceName:string, fields:Array<string>, validate:Function)

-sliceName : string

the name of your form and the key to where your form's state will be mounted in the Redux store

- fields : Array<string>

a list of all your fields in your form.

- validation : Function

your validation function

@reduxForm(sliceName:string)

-sliceName : string

the name of your form and the key to where your form's state will be mounted in the Redux store

Running Example

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.