【问题标题】:Uncaught TypeError: Cannot read property 'type' of undefined at start of switch function未捕获的类型错误:在开关函数开始时无法读取未定义的属性“类型”
【发布时间】:2017-07-20 11:27:17
【问题描述】:

我正在尝试使用将我的应用程序从纯反应转移到 redux-react。我为 onClick 做了一个动作和减速器,但是在尝试以开发模式启动应用程序后,我收到了这个错误

Uncaught TypeError: Cannot read property 'type' of undefined at reducerDomMethods (manMethodsReducers.js:12) 

这是这一行

switch (action.type) {  

这是我的代码

减速器

export default function reducerDomMethods(state={
isClicked: false,
}, action) {
switch (action.type) {
    case "CLICK_OPEN": {
        return {
            ...state,
            isClicked: true
        }
    }

    case "CLICK_CLOSE": {
        return{
            ...state,
            isClicked:false
        }
    }

        return state;
  }
}

动作

export function clicking(isClicked) {

return function (dispatch) {

            if( isClicked === true){
                dispatch({type: "CLICK_OPEN",isClicked: true});
            }else {
                dispatch({type: "CLICK_CLOSE",isClicked: false});
            }
   }
}

组合减速器

    import { combineReducers } from "redux"

    import cityName from "./apiReducers"
    import nameOfCity from "./apiReducers"
    import weatherDescription from "./apiReducers"
    import windSpeed from "./apiReducers"
    import temperature from "./apiReducers"
    import maxTemperature from "./apiReducers"
    import minTemperature from "./apiReducers"
    import isClicked from "./manMethodsReducers"

    export default combineReducers({
        cityName,
        nameOfCity,
        weatherDescription,
        windSpeed,
        temperature,
        maxTemperature,
        minTemperature,
        isClicked
    })

商店

import { applyMiddleware, createStore } from "redux"

import logger from "redux-logger"
import thunk from "redux-thunk"
import promise from "redux-promise-middleware"

import reducer from "./reducers"
import reducerDomMethods from "./reducers"

const middleware = applyMiddleware(promise(), thunk, logger())

export default createStore( reducer , reducerDomMethods, middleware)

连接

    import {connect} from "react-redux"

@connect((store) => {

    return {
       nameOfCity:store.nameOfCity.nameOfCity,
       weatherDescription:store.weatherDescription.weatherDescription,
       windSpeed:store.windSpeed.windSpeed,
       temperature:store.temperature.temperature,
       maxTemperature:store.maxTemperature.maxTemperature,
       minTemperature:store.minTemperature.minTemperature,
       isClicked:store.isClicked.isClicked,
      }
     })

编辑:这是我导入发送操作的地方

        import React, {Component} from 'react';
        import SearchBar from '../components/SearchBar';
        import {connect} from "react-redux"
        import {fetchWeatherData} from "../actions/weather-apiActions";
        import {clicking} from '../actions/manMethodsActions'

        @connect((store) => {
            return {
                nameOfCity:store.nameOfCity.nameOfCity,
                weatherDescription:store.weatherDescription.weatherDescription,
                windSpeed:store.windSpeed.windSpeed,
                temperature:store.temperature.temperature,
                maxTemperature:store.maxTemperature.maxTemperature,
                minTemperature:store.minTemperature.minTemperature,
                isClicked:store.isClicked.isClicked,
            }
        })

        class FormContainer extends Component {

            handleFormSubmit(e) {
                e.preventDefault();
                var cName = e.target.CityName.value;
                console.log(cName);
                let isClicking = false;
                this.props.dispatch(clicking(isClicking));
                this.props.dispatch(fetchWeatherData(cName));
            }

            render() {

                return (


                    <div>
                    <form onSubmit={this.handleFormSubmit.bind(this)}>
                        <label>{this.props.label}</label>


                        <SearchBar
                                name="CityName"
                                type="text"
                                value={this.props.cityName}
                                placeholder="search"
                            />

                        <button type="submit" className="" value='Submit' placeholder="Search">Search</button>
                    </form>
                    </div>
                );
            }
        }

        export {FormContainer};

【问题讨论】:

  • 动作未定义。检查您是否正在发送它。
  • 我是redux的菜鸟,我如何检查我是否没有在应用程序中触发它
  • 您能否提供一个代码,用于导入和发送操作?
  • 我用你问的代码编辑和添加了
  • 你可以在reducer参数上使用action={}

标签: javascript reactjs ecmascript-6 redux react-redux


【解决方案1】:

您的clicking 操作返回一个函数,并且您正在使用this.props.dispatch(clicking(isClicking)); 调度该函数。如果你想保持动作的嵌套结构,那么你应该将调度修改为this.props.dispatch(clicking(isClicking)());,它会自动调用从clicking动作接收到的函数。

但是,建议的用途是修改您的 clicking 操作...

export function clicking(isClicked) {
  dispatch({ type: "CLICK_OPEN", isClicked });
}

请记住,您可以在操作文件中导入您的商店并使用store.dispatch 来调度操作。您不需要从组件中传递dispatch 函数。

【讨论】:

  • 嗯,这意味着 dispatch 应该只在你调用它的函数时才被传递?
猜你喜欢
  • 2015-11-01
  • 2021-12-22
  • 1970-01-01
  • 2013-07-04
  • 1970-01-01
  • 2019-10-15
  • 2017-07-26
  • 1970-01-01
相关资源
最近更新 更多