Question

我的redux存在问题。这是我第一次在React中使用它。我成功地使用它来记录和注册用户。但是，我有一个在后端创建的对象数组，我正在使用axios获取。 Axios记录数据，我的动作创建者也将数据记录在有效负载中。但是，它不会更新我的新状态。我不知道我做错了什么，因为我尝试的方式与我的登录和注册状态完全相同，但这些只是布尔值。我用谷歌搜索并寻找解决方案。我尝试映射新数组，Object.assign和许多其他人，但我似乎无法让它工作。在状态中创建新数组有什么特别的方法吗？或者我可以将它分配给action.payload？我感谢所有的帮助

// store.js

import { applyMiddleware, createStore } from 'redux';
import logger from 'redux-logger';
import thunk from 'redux-thunk';

import reducer from './reducers/reducer';

const middleware = applyMiddleware(logger, thunk);

export default createStore(reducer, middleware);

// rootReducer.js

import { combineReducers } from 'redux';

import registerReducer from './registerReducer';
import loginReducer from './loginReducer';
import productsReducer from './products';

export default combineReducers({
  registerReducer,
  loginReducer,
  productsReducer
});

// productsReducer //我相信这里肯定是错的

import { SHOW_PRODUCTS, SELECT_PRODUCT } from '../actions/products';

const initialState = {
  productsList: []
};

const productsReducer = (state = initialState, action) => {
  switch (action.type) {
    case SHOW_PRODUCTS: 
      return {...state, productsList: action.payload}
  }
  return state;
}

export default productsReducer;

// actions.js

import { SHOW_PRODUCTS, SELECT_PRODUCT } from './constants';

export function showProducts(products) {
  return {
    type: SHOW_PRODUCTS,
    payload: products
  };
}

// component.js

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

import ProductsList from './ProductsList';
import { showProducts }  from '../actions/products';


class Home extends Component {
  constructor(props) {
    super(props);
  }

  componentWillMount() {
    this.props.getProducts(); 
  }

  render() {
    return(
      <div>Home Page
        <ProductsList />
      </div>
    )
  }
}

const mapStateToProps = (state) => {
  return {
    productsList: state.productsReducer.productsList
  };
}

const mapDispatchToProps = (dispatch) => {
  return {
    getProducts: () => {
      axios.get('http://localhost:5000/product/list')
      .then((res) => {
        console.log(res.data);
        dispatch(showProducts(res.data))
      })
      .catch(err => console.log(err))
    }
  }
}

export default connect(mapStateToProps, mapDispatchToProps)(Home);

我还使用我的redux记录器包含了一个图像链接。

https://i.stack.imgur.com/bTnYh.png

这里可能是一个非常小的，愚蠢的错误，因为我对React很新，而且对Redux来说是全新的

Answer 1

你有一个错误，我不知道你是否是一个短信，但在productsReducer.js constants actions constants来自import { SHOW_PRODUCTS, SELECT_PRODUCT } from '../actions/constants'; // <- from constants instead const initialState = { productsList: [] }; const productsReducer = (state = initialState, action) => { switch (action.type) { case SHOW_PRODUCTS: return {...state, productsList: action.payload} } return state; } export default productsReducer;时应该来自reducer：

case

因此undefined {{1}}实际上不应该是{{1}}，因为它是{{1}}，因此会返回初始状态。

Answer 2

我相信mapStateToProps你想要做以下事情：

const mapStateToProps = (state) => {
    return {
        productsList: state.productsList
    };
}

要确认传递productsList，您是否可以添加一个简单的循环到render component.js函数，如下所示：

render() {
    const { productsList } = this.props;
    return(
        <div>
            Home Page
            {productsList.map((product, index) => (
                <div key={index}>{product.PROPERTY_NAME_HERE}</div>
            ))}
        </div>
    )
}

Answer 3

我用减速机做的方式是

import { SHOW_PRODUCTS, SELECT_PRODUCT } from '../actions/products';

const initialState = {
  productsList: []
};

const productsReducer = (state = initialState, action) => {
  switch (action.type) {
    case SHOW_PRODUCTS:
      let nextState = {...state};
      nextState.productsList = action.payload
      return nextState;
  }
  return state;
}

export default productsReducer;

Answer 4

尝试这种方式：

componentWillMount() {
  this.getProducts(); 
}

getProducts() {
  axios.get('http://localhost:5000/product/list')
  .then((res) => {this.props.showProducts(res.data);})
  .catch(err => console.log(err));
}

const mapDispatchToProps = dispatch => ({
  showProducts: (data) => {
    dispatch(showProducts(data));
  },
});

Redux状态不更新数组

4 个答案: