React + Redux - What's the best way to handle CRUD in a form component?

Question

I found the Redux Form package. It does a really good job!

So, you can use Redux with React-Redux.

First you have to create a form component (obviously):

import React from 'react';
import { reduxForm } from 'redux-form';
import validateContact from '../utils/validateContact';

class ContactForm extends React.Component {
  render() {
    const { fields: {name, address, phone}, handleSubmit } = this.props;
    return (
      <form onSubmit={handleSubmit}>
        <label>Name</label>
        <input type="text" {...name}/>
        {name.error && name.touched && <div>{name.error}</div>}

        <label>Address</label>
        <input type="text" {...address} />
        {address.error && address.touched && <div>{address.error}</div>}

        <label>Phone</label>
        <input type="text" {...phone}/>
        {phone.error && phone.touched && <div>{phone.error}</div>}

        <button onClick={handleSubmit}>Submit</button>
      </form>
    );
  }
}

ContactForm = reduxForm({
  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 default ContactForm;

After this, you connect the component which handles the form:

import React from 'react';
import { connect } from 'react-redux';
import { initialize } from 'redux-form';
import ContactForm from './ContactForm.react';

class App extends React.Component {

  handleSubmit(data) {
    console.log('Submission received!', data);
    this.props.dispatch(initialize('contact', {})); // clear form
  }

  render() {
    return (
      <div id="app">
        <h1>App</h1>
        <ContactForm onSubmit={this.handleSubmit.bind(this)}/>
      </div>
    );
  }

}

export default connect()(App);

And add the redux-form reducer in your combined reducers:

import { combineReducers } from 'redux';
import { appReducer } from './app-reducers';
import { reducer as formReducer } from 'redux-form';

let reducers = combineReducers({
  appReducer, form: formReducer // this is the form reducer
});

export default reducers;

And the validator module looks like this:

export default function validateContact(data, props) {
  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;
}

After the form is completed, when you want to fill all the fields with some values, you can use the initialize function:

componentWillMount() {
  this.props.dispatch(initialize('contact', {
    name: 'test'
  }, ['name', 'address', 'phone']));
}

Another way to populate the forms is to set the initialValues.

ContactForm = reduxForm({
  form: 'contact',                      // the name of your form and the key to
  fields: ['name', 'address', 'phone'], // a list of all your fields in your form
  validate: validateContact             // a synchronous validation function
}, state => ({
  initialValues: {
    name: state.user.name,
    address: state.user.address,
    phone: state.user.phone,
  },
}))(ContactForm);

If you got any other way to handle this, just leave a message! Thank you.

UPDATE: its 2018 and I'll only ever use Formik (or Formik-like libraries)

There is also react-redux-form (step-by-step), which seems exchange some of redux-form's javascript (& boilerplate) with markup declaration. It looks good, but I've not used it yet.

A cut and paste from the readme:

import React from 'react';
import { createStore, combineReducers } from 'redux';
import { Provider } from 'react-redux';
import { modelReducer, formReducer } from 'react-redux-form';

import MyForm from './components/my-form-component';

const store = createStore(combineReducers({
  user: modelReducer('user', { name: '' }),
  userForm: formReducer('user')
}));

class App extends React.Component {
  render() {
    return (
      <Provider store={ store }>
        <MyForm />
      </Provider>
    );
  }
}

./components/my-form-component.js

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

class MyForm extends React.Component {
  handleSubmit(val) {
    // Do anything you want with the form value
    console.log(val);
  }

  render() {
    let { user } = this.props;

    return (
      <Form model="user" onSubmit={(val) => this.handleSubmit(val)}>
        <h1>Hello, { user.name }!</h1>
        <Field model="user.name">
          <input type="text" />
        </Field>
        <button>Submit!</button>
      </Form>
    );
  }
}

export default connect(state => ({ user: state.user }))(MyForm);

Edit: Comparison

The react-redux-form docs provide a comparison vs redux-form:

https://davidkpiano.github.io/react-redux-form/docs/guides/compare-redux-form.html

For those who doesn't care about an enormous library for handling form related issues, I would recommend redux-form-utils.

It can generate value and change handlers for your form controls, generate reducers of the form, handy action creators to clear certain(or all) fields, etc.

All you need to do is assemble them in your code.

By using redux-form-utils, you end up with form manipulation like following:

import { createForm } from 'redux-form-utils';

@createForm({
  form: 'my-form',
  fields: ['name', 'address', 'gender']
})
class Form extends React.Component {
  render() {
    const { name, address, gender } = this.props.fields;
    return (
      <form className="form">
        <input name="name" {...name} />
        <input name="address" {...address} />
        <select {...gender}>
          <option value="male" />
          <option value="female" />
        </select>
      </form>
    );
  }
}

However, this library only solves problem C and U, for R and D, maybe a more integrated Table component is to antipate.

Just another thing for those who want to create fully controlled form component without using oversized library.

ReduxFormHelper - a small ES6 class, less than 100 lines:

class ReduxFormHelper {
  constructor(props = {}) {
    let {formModel, onUpdateForm} = props
    this.props = typeof formModel === 'object' &&
      typeof onUpdateForm === 'function' && {formModel, onUpdateForm}
  }

  resetForm (defaults = {}) {
    if (!this.props) return false
    let {formModel, onUpdateForm} = this.props
    let data = {}, errors = {_flag: false}
    for (let name in formModel) {
      data[name] = name in defaults? defaults[name] :
        ('default' in formModel[name]? formModel[name].default : '')
      errors[name] = false
    }
    onUpdateForm(data, errors)
  }

  processField (event) {
    if (!this.props || !event.target) return false
    let {formModel, onUpdateForm} = this.props
    let {name, value, error, within} = this._processField(event.target, formModel)
    let data = {}, errors = {_flag: false}
    if (name) {
      value !== false && within && (data[name] = value)
      errors[name] = error
    }
    onUpdateForm(data, errors)
    return !error && data
  }

  processForm (event) {
    if (!this.props || !event.target) return false
    let form = event.target
    if (!form || !form.elements) return false
    let fields = form.elements
    let {formModel, onUpdateForm} = this.props
    let data = {}, errors = {}, ret = {}, flag = false
    for (let n = fields.length, i = 0; i < n; i++) {
      let {name, value, error, within} = this._processField(fields[i], formModel)
      if (name) {
        value !== false && within && (data[name] = value)
        value !== false && !error && (ret[name] = value)
        errors[name] = error
        error && (flag = true)
      }
    }
    errors._flag = flag
    onUpdateForm(data, errors)
    return !flag && ret
  }

  _processField (field, formModel) {
    if (!field || !field.name || !('value' in field))
      return {name: false, value: false, error: false, within: false}
    let name = field.name
    let value = field.value
    if (!formModel || !formModel[name])
      return {name, value, error: false, within: false}
    let model = formModel[name]
    if (model.required && value === '')
      return {name, value, error: 'missing', within: true}
    if (model.validate && value !== '') {
      let fn = model.validate
      if (typeof fn === 'function' && !fn(value))
        return {name, value, error: 'invalid', within: true}
    }
    if (model.numeric && isNaN(value = Number(value)))
      return {name, value: 0, error: 'invalid', within: true}
    return {name, value, error: false, within: true}
  }
}

It doesn't do all the work for you. However it facilitates creation, validation and handling of a controlled form component. You may just copy & paste the above code into your project or instead, include the respective library - redux-form-helper (plug!).

How to use

The first step is add specific data to Redux state which will represent the state of our form. These data will include current field values as well as set of error flags for each field in the form.

The form state may be added to an existing reducer or defined in a separate reducer.

Furthermore it's necessary to define specific action initiating update of the form state as well as respective action creator.

Action example:

export const FORM_UPDATE = 'FORM_UPDATE' 

export const doFormUpdate = (data, errors) => {
  return { type: FORM_UPDATE, data, errors }
}
...

Reducer example:

...
const initialState = {
  formData: {
    field1: '',
    ...
  },
  formErrors: {
  },
  ...
}

export default function reducer (state = initialState, action) {
  switch (action.type) {
    case FORM_UPDATE:
      return {
        ...ret,
        formData: Object.assign({}, formData, action.data || {}),
        formErrors: Object.assign({}, formErrors, action.errors || {})
      }
    ...
  }
}

The second and final step is create a container component for our form and connect it with respective part of Redux state and actions.

Also we need to define a form model specifying validation of form fields. Now we instantiate ReduxFormHelper object as a member of the component and pass there our form model and a callback dispatching update of the form state.

Then in the component's render() method we have to bind each field's onChange and the form's onSubmit events with processField() and processForm() methods respectively as well as display error blocks for each field depending on the form error flags in the state.

The example below uses CSS from Twitter Bootstrap framework.

Container Component example:

import React, {Component} from 'react';
import {connect} from 'react-redux'
import ReduxFormHelper from 'redux-form-helper'

class MyForm extends Component {
  constructor(props) {
    super(props);
    this.helper = new ReduxFormHelper(props)
    this.helper.resetForm();
  }

  onChange(e) {
    this.helper.processField(e)
  }

  onSubmit(e) {
    e.preventDefault()
    let {onSubmitForm} = this.props
    let ret = this.helper.processForm(e)
    ret && onSubmitForm(ret)
  }

  render() {
    let {formData, formErrors} = this.props
    return (
  <div>
    {!!formErrors._flag &&
      <div className="alert" role="alert">
        Form has one or more errors.
      </div>
    }
    <form onSubmit={this.onSubmit.bind(this)} >
      <div className={'form-group' + (formErrors['field1']? ' has-error': '')}>
        <label>Field 1 *</label>
        <input type="text" name="field1" value={formData.field1} onChange={this.onChange.bind(this)} className="form-control" />
        {!!formErrors['field1'] &&
        <span className="help-block">
          {formErrors['field1'] === 'invalid'? 'Must be a string of 2-50 characters' : 'Required field'}
        </span>
        }
      </div>
      ...
      <button type="submit" className="btn btn-default">Submit</button>
    </form>
  </div>
    )
  }
}

const formModel = {
  field1: {
    required: true,
    validate: (value) => value.length >= 2 && value.length <= 50
  },
  ...
}

function mapStateToProps (state) {
  return {
    formData: state.formData, formErrors: state.formErrors,
    formModel
  }
}

function mapDispatchToProps (dispatch) {
  return {
    onUpdateForm: (data, errors) => {
      dispatch(doFormUpdate(data, errors))
    },
    onSubmitForm: (data) => {
      // dispatch some action which somehow updates state with form data
    }
  }
}

export default connect(mapStateToProps, mapDispatchToProps)(MyForm)

Demo