redux-store.md

layout	page
permalink	/redux-store/

---

The Goal

• Create a store using react-redux to manage everything
• Put it in index.js
• Wrap it in a Provider element from react-redux

// ...as before...
import robotsSearch from './reducers'
import { createStore } from 'redux'
import { Provider } from 'react-redux'

const store = createStore(robotsSearch)

ReactDOM.render(
  <Provider store={store}>
    <App/>
  </Provider>,
  document.getElementById('root')
);

• createStore creates a Redux store
  • We still need to provide specific actions and dispatchers
• Provider is a way to create the equivalent of a global variable
  • Adds named data to the props of all of the elements within its scope
• We won't actually refer to store ourselves
  • It will be connected when we wire everything together

---

Connecting the Pieces

• Modify App.js (our container)
• connect takes two functions
• Wraps the App class with something that knows how to talk to a default store
  • This code relies on the store variable created by the Provider

// ...as before...
import { connect } from "react-redux";
import { setSearchTerm } from "../actions";

// ...map state to properties...

// ...map dispatch function to properties...

class App extends Component {
  // ...constructor...
  // ...initial data fetch...
  // ...render...
}

export default connect(mapStateToProps, mapDispatchToProps)(App)

---

Mapping State to Properties

• Given a state, generate the change to the properties

const mapStateToProps = state => {
  return { searchTerm: state.searchTerm };
};

---

Mapping Dispatch Function to Properties

const mapDispatchToProps = dispatch => {
  return {
    onSearchChange: event => dispatch(setSearchTerm(event.target.value))
  };
};

---

Constructor

• Initialize state as usual

class App extends Component {
  constructor() {
    super()
    this.state = { robots: [], isPending: true }
  }
}

---

Initial Data Fetch

• As before

  componentDidMount() {
    apiCall("https://jsonplaceholder.typicode.com/users").then(
      response => this.setState({ robots: response, isPending: false })
    );
  }

---

Rendering

• Looks pretty much the same as well
  • Which is the point
• Get onSearchChange from the properties
  • This is the function named in the object returned by mapDispatchToProps
  • react-redux wires all of this up for us

  render() {
    const { robots, isPending } = this.state;
    const filteredRobots = robots.filter(
      robot => 
        robot.name.toLowerCase().includes(this.props.searchTerm.toLowerCase())
    );
    return (
      <div className="tc">
        <h1>RoboDex</h1>
        <SearchBox onSearchChange={this.props.onSearchChange} />
        <Scroll>
          {
            isPending
              ? <h2>Loading...</h2>
              : <CardList robots={filteredRobots} />
          }
        </Scroll>
      </div>
    );
  }
}