List App connection errors in ListList component

Index of List App

import React from 'react';
import ReactDOM from 'react-dom';
import { Route, Link, BrowserRouter as Router, Switch } from 'react-router-dom';
import  { Provider } from 'react-redux';
import { store } from './REDUX/store';
import './index.css';
import App from './App';
import { Manage } from './components/Delta/Manage';
import { NewList } from './components/Delta/NewList';
import { Share } from './components/Delta/Share';
import { Banner } from './components/Banner';
import { AddTo } from './components/AddTo';
import ListList from './components/ListList';
import * as serviceWorker from './serviceWorker';


const routing = (
  <Provider store={store}>
    <Router>
      <div className="App">
        <Banner />
        <div className="nav">
          <Link to="/" className="menuOption"><h3>New List</h3></Link>
          <Link to="/manage" className="menuOption"><h3>Manage</h3></Link>
          <Link to="/share" className="menuOption"><h3>Share Lists</h3></Link>      
        </div>
        <ListList /> {/*wrap export in withRouter*/}
        <div class="functionBox">
          <div class="functionBoxGrid">
            <AddTo />
            <Switch className="Delta">
              <Route exact path="/" component={NewList} />
              <Route path="/manage" component={Manage} />
              <Route path="/share" component={Share} />
            </Switch>
          </div>
        </div>
      </div>
    </Router>
  </Provider>  
);

ReactDOM.render(routing, document.getElementById('root'));

ListList component

import React from 'react';
import { connect } from 'react-redux';
//import PropTypes from 'prop-types'
import '../App.css';

class ListList extends React.Component {
    constructor(props) {
        super(props);
    }
    render() {
        let allShops = this.props.masterList.map(listItem => listItem.stores); //generates error
        let shops = [];
        for (let itemList of allShops) {
            for (let shop of itemList) {
                if (shops.indexOf(shop) === -1) {
                    shops.push(shop);
                }
            }
        };
        return(
            <div className="listBox">
                <div className="listBoxTitle">
                    <h3>Shopping <br/> Lists</h3>
                </div>
                {shops.map(shop =>
                    <div className="listButton">
                        <p>{shop}</p>
                    </div>
                )}
            </div>
        )
    }
};


const mapStateToProps = (state) => {  
    return { 
        masterList: state.masterList //generates error
    }
}

export default connect(mapStateToProps)(ListList)

REDUx Action Creators

import { constants } from './actionTypes';

//list actions

let nextId = 10001;

export const addItem = (itemName, quantity, units, notes, stores)  => {
    //payload =  itemName, quantity, units, notes, stores 
    return { 
        type: constants.ADD_ITEM, 
        id: nextId++, 
        checked: false,
        itemName, 
        quantity, 
        units, 
        notes, 
        stores //array
    }
}; 


export const toggleCheck = id => {
    return { 
        type: constants.TOGGLE_CHECK, 
        id 
    }
};

export const removeChecked = () => {
    return {
        type: constants.REMOVE_CHECKED, 
    }
};

export const deleteList = shop => {
    return {
        type: constants.DELETE_LIST, 
            shop
    }
};

REDUX Reducer

import { constants } from './actionTypes';

export const reducer = (state, action) => {
    switch (action.type) {
        case constants.ADD_ITEM:
            return Object.assign({}, state, {
                masterList: [ 
                    ...state.masterList, 
                        {
                            id: action.id,
                            checked: false,
                            item: action.item,
                            quantity: action.quantity,
                            units: action.units,
                            notes: action.notes,
                            stores: action.stores
                        }
                    ]
            })
        case constants.TOGGLE_CHECK:
            return Object.assign({}, state, {
                masterList: state.masterList.map((listItem) => {
                    return listItem.id === action.id ?
                    Object.assign({}, {checked: !listItem.checked}) : listItem
                })
            })
        case constants.REMOVE_CHECKED:
            return Object.assign({}, state, {
                masterList: state.masterList.filter((listItem)=> {
                    return listItem.checked === true 
                })
            })
        case constants.DELETE_LIST:
            return Object.assign({}, state, {
                masterList: state.masterlist.map((listItem)=> {
                    listItem.stores.filter(shop => {
                        return shop !== action.shop
                    })
                    return listItem.stores.length > 0 
                })
            })
    }
}

REDUX store

import { createStore } from 'redux';
import { reducer } from './reducers';
import { InitialState } from './initialState';

export const store = createStore( 
                reducer, 
                InitialState)
                
const InitialState = {
    masterList: [ 
        {
            "id": 10000,
            "checked": false,
            "item": "item name",
            "quantity": 1,
            "units": "boxes",
            "notes": "always optional",
            "stores": ["Your", "Stores", "Here"]
        }
    ]
}