Pseudo Redux code

redux.js

// Component

class CarList extends Component {
  componentWillMount() {
    this.props.fetchCars(); // dispatching an action creator
  }

  render() {
    if (this.props.error) {
      // show some message
    }
    this.props.cars.map(...);
  }
}

function mapStateToProps(state) {
  return {
    cars: state.cars.all;
  };
}


// Actions
fetchCars() { // action creator
    try {
        const data = axios.get();
        return fetchCarsSuccess(data);
    } catch (e) {
        return fetchCarsError(e);
    }   
}

fetchCarsSuccess(data) {
  return { // action // unnamed, identified by it's type
     type: 'FETCH_CARS_SUCCESS',
     payload: data
  };   
}

fetchCarsError(e) {
  return { // action // unnamed, identified by it's type
     type: 'FETCH_CARS_ERROR',
     payload: e
  };    
}


// Middleware
function errorLogMidleware(state, action) {
  if (action.payload instanceof Error) {
    logItOnMyErrorTrackingApp(action.payload);
  }
  return state;
}


// Reducers

state: {
  cars: carReducer(...)
}

const INITIAL_STATE = {
    all: [],
    loading: false,
    error: null

};

export default function carReducer(state = INITIAL_STATE, action) { // reducer
  switch (action.type) {
    case 'FETCH_CARS_SUCCESS':
      return {
        ...state,  // Object spread
        all: action.payload,
        loading: false,
        error: null
      };
    case 'FETCH_CARS_ERROR':
      return {
        ...state,
        loading: false,
        error: action.payload
      }
  }
}