Reactjs 处于redux状态的Push数组元素返回'undefined'`

我想用redux来解决这个问题。它在redux不起作用。我的代码哪里出了问题

action/index.js： 减速器/mainReducer.js reducers/index.js： 我就是这样使用它们的：

import React，{useffect}来自“React”；
从“./functions/getCities”导入getCities；
从“/RadioList”导入放射科医生；
从“react redux”导入{connect}
从“../redux/actions”导入{setCities}
功能状态列表（道具）{
让标签=[]，
城市=[]；
useffect（（）=>{
getCities（props.cityState）。然后（（数组）=>{
for（设i=0；i
)
}
);
}
const mapStatesToProps=状态=>{
返回{
城市：state.setCitiesReducer.city，
}
}
导出默认连接（MapStateStorops，{setCities}）（ListOfStates）；

错误是： TypeError:无法读取未定义的属性“map”

请尝试以下操作：

function ListOfStates(props) {
    let labels = [],
        cities = [];
    useEffect(() => {
       getCities(props.cityState).then((array) => {
           for (let i = 0; i < array.response.length; i++)
               cities.push(array.response[i]);
           props.setCities([...cities]);
       });
    }, []);
    return (<>
        {
            props.city.map((labels, index) =>
                <RadioList active={(labels === props.active)} key={index} label={labels}/>)
        }
    </>);
}

const mapStatesToProps = state => {
    return {
        city: state.setCitiesReducer.cities,
    }
}
export default connect(mapStatesToProps, {setCities})(ListOfStates);

功能列表状态（道具）{
让标签=[]，
城市=[]；
useffect（（）=>{
getCities（props.cityState）。然后（（数组）=>{
for（设i=0；i
)
}
);
}
const mapStatesToProps=状态=>{
返回{
城市：state.setCitiesReducer.cities，
}
}
导出默认连接（MapStateStorops，{setCities}）（ListOfStates）；
的答案帮助我改进最正确的答案

功能列表状态（道具）{
让标签=[]，
城市=[]；
useffect（（）=>{
getCities（props.cityState）。然后（（数组）=>{
for（设i=0；i）：(
道具.城市['0'].地图（（标签，索引）=>
)
)}
);
}
const mapStatesToProps=状态=>{
返回{
城市：state.setCitiesReducer.cities，
}
}
导出默认连接（MapStateStorops，{setCities}）（ListOfStates）；

import {
    GET_CITIES_BY_SPECIAL_STATE
} from '../actions/types';

const initialState = {
    cities: []
}
const mainReducers = (state = initialState, action) => {
    switch (action.type) {
        case GET_CITIES_BY_SPECIAL_STATE:
            return {...state, cities: state.cities.concat(action.payload)}
        default:
            return state;
    }
}
export default mainReducers; 

import { combineReducers } from 'redux';
import mainReducers from "../reducers/main";
const reducers = combineReducers({
    setCitiesReducer: mainReducers
});
export default reducers;

import React, {useEffect} from "react";
import getCities from "../functions/getCities";
import RadioList from "./RadioList";
import {connect} from 'react-redux'
import {setCities} from '../redux/actions'

function ListOfStates(props) {
    let labels = [],
        cities = [];
    useEffect(() => {
       getCities(props.cityState).then((array) => {
           for (let i = 0; i < array.response.length; i++)
               cities.push(array.response[i]);
           props.setCities([...cities]);
       });
    }, []);
    return (<>
        {
            props.city.map((labels, index) =>
                <RadioList active={(labels === props.active)} key={index} label={labels}/>)
        }
    </>);
}

const mapStatesToProps = state => {
    return {
        city: state.setCitiesReducer.city,
    }
}
export default connect(mapStatesToProps, {setCities})(ListOfStates);

function ListOfStates(props) {
    let labels = [],
        cities = [];
    useEffect(() => {
       getCities(props.cityState).then((array) => {
           for (let i = 0; i < array.response.length; i++)
               cities.push(array.response[i]);
           props.setCities([...cities]);
       });
    }, []);
    return (<>
        {
            props.city.map((labels, index) =>
                <RadioList active={(labels === props.active)} key={index} label={labels}/>)
        }
    </>);
}

const mapStatesToProps = state => {
    return {
        city: state.setCitiesReducer.cities,
    }
}
export default connect(mapStatesToProps, {setCities})(ListOfStates);


function ListOfStates(props) {
    let labels = [],
        cities = [];
    useEffect(() => {
       getCities(props.cityState).then((array) => {
           for (let i = 0; i < array.response.length; i++)
               cities.push(array.response[i]);
           props.setCities([...cities]);
       });
    }, []);
    return (<>
    {(props.city['0'] === undefined) ? (<p>Loading...</p>) : (
        props.city['0'].map((labels, index) =>
            <RadioList active={(labels === props.active)} key={index} label={labels}/>)
    )}
</>);
}

const mapStatesToProps = state => {
    return {
        city: state.setCitiesReducer.cities,
    }
}
export default connect(mapStatesToProps, {setCities})(ListOfStates);