未捕获错误：无法在“Connect(CharacterList)”的上下文或道具中找到“store”.将根组件包装在a中,或者将“store”显式传递为“Connect(CharacterList)”的prop.

characterlist.js

import React,{ Component } from 'react';
import { connect } from 'react-redux';

class CharacterList extends Component {
    render() {
        console.log('this.props',this.props);
        return (
            <div>
                <h4>characters</h4>
            </div>
        )
    }

}
function mapStateToProps(state) {
    return {
        characters: state.characters
    }
}

export default connect(mapStateToProps,null)(CharacterList);

app.js

import React,{Component} from 'react';
import CharacterList from './CharacterList';

class App extends Component {
    render() {
        return (
            <div>
                <h2>SUPER SQUAD</h2>
                <CharacterList />
            </div>
        )
    }
} 
export default App;

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import App from './Components/App';

import { createStore } from 'redux';
import { Provider } from 'react-redux';

import rootReducers from './reducers';
import { addCharacterById } from './actions';


const store = createStore(rootReducers);
console.log(store.getState());
store.subscribe(() => console.log('store',store.getState()))
store.dispatch(addCharacterById(3));

ReactDOM.render(
    <Provider>
        <App />
     </Provider>,document.getElementById('root')
)

character.js(在reducers文件夹中)

import characters_json from '../Data/characters.json';
import { ADD_CHARACTER } from '../actions';

function characters(state = characters_json,action) {
    switch(action.type) {
        case ADD_CHARACTER:
        let characters = state.filter(item => item.id !== action.id);
        return characters;
        default:
            return state;
    }
}
export default characters;

heroes.js(redurs文件夹)

import { ADD_CHARACTER } from '../actions';
import {createCharacter} from './helper';

function heroes(state = [],action) {
    switch(action.type) {
        case ADD_CHARACTER:
        let heroes = [...state,createCharacter(action.id)];
        return heroes;
        default:
        return state;
    }
}
export default heroes;

helper.js(redurs文件夹)

import characters_json from '../Data/characters.json';

export function createCharacter(id) {
    let character = characters_json.find(c => c.id === id);
    return character;
}

index.js(redurs文件夹)

import { combineReducers } from 'redux';
import characters from './characters_reducer';
import heroes from './heroes_reducer';


const rootReducer = combineReducers({
    characters,heroes
})
export default rootReducer;

index.js(动作文件夹)

export const ADD_CHARACTER = 'ADD_CHARACTER';

export function addCharacterById(id) {
    const action = {
        type:ADD_CHARACTER,id
    }
    return action;
}

组件中出现上述错误：

在Connect(CharacterList)中(在App.js：9)

在div(在App.js：7)

在App中(在index.js：19)

在提供者(在index.js：18)

请帮我…？