Redux Form Example

Redux Form is a sample app made with React Native, Redux, and Redux-Form and NativeBase as the main Libraries at work here.
This is a simple step-by-step tutorial to get familiar with basic concepts of Redux (used for state management), and Redux-Form. This simple App should get you familiar with these Libraries and their use case.

Find Full code here

1. Aim

We aim to create a single page application that uses Redux-Form and has validation functionality.

2. Installation

SetUp React Native Project
SetUp a React Native project. Refer this for more information about setting up a React Native project.
Installing Libraries
With a React Native project SetUp, We can now install all required Libraries as follows.

a. Redux and react-redux
In your terminal enter the following
```
npm install redux react-redux --save
```
b. redux-form
```
npm install --save redux-form
```
c. NativeBase
```
npm install native-base --save
```
Configure all dependencies by running the following command
```
react-native link
```

Note: You might have some problems setting up the project due to version conflicts, make sure you use same versions as mentioned below in the package.json By the end of Installation, your package.json file should look something like this.

3. SetUp

Create a src folder at root of your project. Create folders compnoents reducers and one file Application.js for our App.

3.1. Reducers

Create a file index.js inside reducers folder. Paste the following code.
Code src/reducers/index.js

import {combineReducers} from 'redux';
import { reducer as formReducer } from 'redux-form';
const reducers = {
  form: formReducer
}
const allReducers= combineReducers(reducers);
export default allReducers;

3.2. Component

Create a file SimpleForm.js inside components folder.
Code src/components/SimpleForm.js

import React , { Component } from 'react';
import Expo from 'expo';
import { View } from 'react-native';
import { Container, Item, Input, Header, Body, Content, Title, Button, Text } from 'native-base';
import { Field,reduxForm } from 'redux-form';
const validate = values => {
  const error= {};
  error.email= '';
  error.name= '';
  var ema = values.email;
  var nm = values.name;
  if(values.email === undefined){
    ema = '';
  }
  if(values.name === undefined){
    nm = '';
  }
  if(ema.length < 8 && ema !== ''){
    error.email= 'too short';
  }
  if(!ema.includes('@') && ema !== ''){
    error.email= '@ not included';
  }
  if(nm.length > 8){
    error.name= 'max 8 characters';
  }
  return error;
};
class SimpleForm extends Component {
  constructor(props){
    super(props);
    this.state={
      isReady: false
    };
    this.renderInput = this.renderInput.bind(this);
  }
  async componentWillMount() {
      await Expo.Font.loadAsync({
        'Roboto': require('native-base/Fonts/Roboto.ttf'),
        'Roboto_medium': require('native-base/Fonts/Roboto_medium.ttf'),
      });
      this.setState({isReady: true});
    }
  renderInput({ input, label, type, meta: { touched, error, warning } }){
    var hasError= false;
    if(error !== undefined){
      hasError= true;
    }
    return( 
      <Item error= {hasError}>
        <Input {...input}/>
        {hasError ? <Text>{error}</Text> : <Text />}
      </Item>
    )
  }
  render(){
     const { handleSubmit, reset } = this.props;
     if (!this.state.isReady) {
      return <Expo.AppLoading />;
    }
    return (
      <Container>
        <Header>
          <Body>
            <Title>Redux Form</Title>
          </Body>
        </Header>
        <Content padder>
          <Field name="email" component={this.renderInput} />
          <Field name="name" component={this.renderInput} />
          <Button block primary onPress= {reset}>
            <Text>Submit</Text>
          </Button>
        </Content>
      </Container>
    )
  }
}
export default reduxForm({
  form: 'test',
  validate
})(SimpleForm)

Explained

We load fonts using loadAsync as defined in previous examples.
Note how we have added validate functionality in the end using reduxForm decorator.
Conditions added to validate are user defined.

3.3. Application

Code src/Application.js

import React , { Component } from 'react';
import allReducers from './reducers/index.js';
import {createStore} from 'redux';
import {Provider} from 'react-redux';
import SimpleForm from './components/SimpleForm.js';
import { Field, reduxForm } from 'redux-form';
const store = createStore(allReducers);
 export default class Application extends Component{
  render(){
    return(
      <Provider store= {store}>
        <SimpleForm />
      </Provider>
    )
  }
}

Explained
Here we import allReducers containing our formReducer and add it to our store. Next we simply pass our store to Provider component.

3.4. Finishing Up

Finally add the Application component in our App.js as follows
Code App.js

import React from 'react';
import { StyleSheet, Text, View } from 'react-native';
import Application from './src/Application.js';
import allReducers from './src/reducers/index.js';
import {createStore} from 'redux';
import {Provider} from 'react-redux';
import { TextInput, TouchableOpacity } from 'react-native';
const store = createStore(allReducers);
export default class App extends React.Component {
  render() {
    return (
      <Application />
    );
  }
}

All done. Our App must work now. It looks awesome(unicorn alert). Build and run for magic.

Redux-Form