React and Redux are often mentioned together, and with good reason. The developer who created Redux was a React developer who wanted to make it easier to share data across different components.
Getting Started with React Redux
class DisplayMessages extends React.Component {
constructor(props) {
super(props)
this.state = {
input:"",
massages: []
}
}
render() {
return <div />
}
};
Manage State Locally First
class DisplayMessages extends React.Component {
constructor(props) {
super(props);
this.state = {
input: '',
messages: []
}
}
handleChange(event){
this.setState({
input: event.target.value,
messages: this.state.messages
})
}
submitMessage(){ this.setState({ input: "", messages: [...this.state.messages, this.state.input] }) }
render() { return ( <div> <h2>Type in a new Message:</h2> { }<input onChange={this.handleChange.bind(this)} value={this.state.input}/> <button onClick={this.submitMessage.bind(this)}>Submit</button> <ul> {this.state.messages.map((x, i)=>{ return <li key={i}>{x}</li> })} </ul>
{ } </div> ); }};
Extract State Logic to Redux
const addMessage = (message) => {
return {
type: ADD,
message
}
}
const messageReducer = (state = [], action) => { switch(action.type) { case ADD: return [...state, action.message] default: return state }}
const store = Redux.createStore(messageReducer)
Use Provider to Connect Redux to React
// Redux:
const ADD = 'ADD';
const addMessage = (message) => { return { type: ADD, message }};
const messageReducer = (state = [], action) => { switch (action.type) { case ADD: return [ ...state, action.message ]; default: return state; }};
const store = Redux.createStore(messageReducer);
// React:
class DisplayMessages extends React.Component { constructor(props) { super(props); this.state = { input: '', messages: [] } this.handleChange = this.handleChange.bind(this); this.submitMessage = this.submitMessage.bind(this); } handleChange(event) { this.setState({ input: event.target.value }); } submitMessage() { this.setState((state) => { const currentMessage = state.input; return { input: '', messages: state.messages.concat(currentMessage) }; }); } render() { return ( <div> <h2>Type in a new Message:</h2> <input value={this.state.input} onChange={this.handleChange}/><br/> <button onClick={this.submitMessage}>Submit</button> <ul> {this.state.messages.map( (message, idx) => { return ( <li key={idx}>{message}</li> ) }) } </ul> </div> ); }};
const Provider = ReactRedux.Provider;
class AppWrapper extends React.Component { render () { return (
<Provider store={store}><DisplayMessages/>
</Provider> ) }};
Map State to Props
const state = [];
const mapStateToProps = (state) => { return { messages: state }}
Map Dispatch to Props
const addMessage = (message) => {
return {
type: 'ADD',
message: message
}
};
const mapDispatchToProps = (dispatch) => { return { submitNewMessage: (message) => { return dispatch(addMessage(message)) } }}
Connect Redux to React
const addMessage = (message) => {
return {
type: 'ADD',
message: message
}
};
const mapStateToProps = (state) => { return { messages: state }};
const mapDispatchToProps = (dispatch) => { return { submitNewMessage: (message) => { dispatch(addMessage(message)); } }};
class Presentational extends React.Component { constructor(props) { super(props); } render() { return <h3>This is a Presentational Component</h3> }};
const connect = ReactRedux.connect;
const ConnectedComponent = connect(mapStateToProps, mapDispatchToProps)(Presentational)
Connect Redux to the Messages App
// Redux:
const ADD = 'ADD';
const addMessage = (message) => { return { type: ADD, message: message }};
const messageReducer = (state = [], action) => { switch (action.type) { case ADD: return [ ...state, action.message ]; default: return state; }};
const store = Redux.createStore(messageReducer);
// React:class Presentational extends React.Component { constructor(props) { super(props); this.state = { input: '', messages: [] } this.handleChange = this.handleChange.bind(this); this.submitMessage = this.submitMessage.bind(this); } handleChange(event) { this.setState({ input: event.target.value }); } submitMessage() { this.setState((state) => { const currentMessage = state.input; return { input: '', messages: state.messages.concat(currentMessage) }; }); } render() { return ( <div> <h2>Type in a new Message:</h2> <input value={this.state.input} onChange={this.handleChange}/><br/> <button onClick={this.submitMessage}>Submit</button> <ul> {this.state.messages.map( (message, idx) => { return ( <li key={idx}>{message}</li> ) }) } </ul> </div> ); }};
// React-Redux:const mapStateToProps = (state) => { return { messages: state }};
const mapDispatchToProps = (dispatch) => { return { submitNewMessage: (newMessage) => { dispatch(addMessage(newMessage)) } }};
const Provider = ReactRedux.Provider;const connect = ReactRedux.connect;
const Container = connect(mapStateToProps, mapDispatchToProps)(Presentational)
class AppWrapper extends React.Component { constructor(props) { super(props); } render() { return ( <Provider store={store}> <Container /> </Provider> ); }};
Extract Local State into Redux
// Redux:
const ADD = 'ADD';
const addMessage = (message) => { return { type: ADD, message: message }};
const messageReducer = (state = [], action) => { switch (action.type) { case ADD: return [ ...state, action.message ]; default: return state; }};
const store = Redux.createStore(messageReducer);
// React:const Provider = ReactRedux.Provider;const connect = ReactRedux.connect;
class Presentational extends React.Component { constructor(props) { super(props); this.state = { input: '',
} this.handleChange = this.handleChange.bind(this); this.submitMessage = this.submitMessage.bind(this); } handleChange(event) { this.setState({ input: event.target.value }); } submitMessage() { this.props.submitNewMessage(this.state.input) this.setState((state) => ({ input: '' })); } render() { return ( <div> <h2>Type in a new Message:</h2> <input value={this.state.input} onChange={this.handleChange}/><br/> <button onClick={this.submitMessage}>Submit</button> <ul> {this.props.messages.map( (message, idx) => { return ( <li key={idx}>{message}</li> ) }) } </ul> </div> ); }};
const mapStateToProps = (state) => { return {messages: state}};
const mapDispatchToProps = (dispatch) => { return { submitNewMessage: (message) => { dispatch(addMessage(message)) } }};
const Container = connect(mapStateToProps, mapDispatchToProps)(Presentational);
class AppWrapper extends React.Component { render() { return ( <Provider store={store}> <Container/> </Provider> ); }};