reactjs js:27未捕获的类型错误:无法读取未定义的属性(正在阅读“params”)

dgjrabp2  于 2023-02-12  发布在  React
关注(0)|答案(1)|浏览(163)

我确信我将要退出的教程已经过时了。我遇到了这个错误ProductDetails.js:27

Uncaught TypeError: Cannot read properties of undefined (reading 'params')

这是我的代码,其中ProductDetails.js:27是分派、警报、错误,match.params.id:

import React, { Fragment, useEffect } from 'react'
            import { Carousel } from 'react-bootstrap'
            
            import Loader from '../layout/Loader'
            import MetaData from '../layout/MetaData'
            
            import { useAlert } from 'react-alert'
            import { useDispatch, useSelector } from 'react-redux'
            import { getProductDetails, clearErrors } from '../../actions/productActions'
            
            const ProductDetails = ({ match }) => {
            
                const dispatch = useDispatch();
                const alert = useAlert();
            
                const { loading, error, product } = useSelector(state => state.productDetails)
            
                useEffect(() => {
                    dispatch(getProductDetails(match.params.id))
                
                    if(error) {
                        alert.error(error);
                        dispatch(clearErrors())
                    }
                
                }, [dispatch, alert, error, match.params.id])
            
            
            
            export default ProductDetails

不知道ProductDetails.js代码有多少,但它在这里,我省略了我的返回函数,因为它说我的帖子主要是代码。下面也是我的App.js代码:

import { BrowserRouter as Router, Route, Routes } from "react-router-dom"
    
    import Header from './components/layout/Header'
    import Footer from './components/layout/Footer'
    
    import Home from './components/Home'
    import ProductDetails from './components/product/ProductDetails'
    
    function App() {
      return (
        <Router>
          <div className="App">
            <Header />
            <div className="container container-fluid">
             <Routes>
              <Route path="/" element={<Home /> } exact />
              <Route path="/product/:id" element={<ProductDetails /> } exact />
             </Routes>
            </div>
            <Footer />
          </div>
        </Router>
      );
    }
    
    export default App;
icnyk63a

icnyk63a1#

值得一提的是,useParams钩子自从React在react-router-dom@5中引入钩子以来一直没有改变。
问题是match只是未定义和/或未作为属性显式传递给此ProductDetails组件。如果您使用const params = useParams()params作为依赖项,则这很可能是渲染循环的原因,因为params将是每个渲染循环的新对象引用。您应该直接引用id参数。
我还建议将效果拆分为两个单独的效果,这样getProductDetails就不会因为error更新而被调度,反之亦然。
示例:

const ProductDetails = () => {
  const dispatch = useDispatch();
  const alert = useAlert();

  const { id } = useParams();

  const { loading, error, product } = useSelector(state => state.productDetails);

  useEffect(() => {
    if (id) {
      dispatch(getProductDetails(id));
    }
  }, [dispatch, id]);

  useEffect(() => {
    if (error) {
      alert.error(error);
      dispatch(clearErrors());
    }
  }, [dispatch, alert, error]);

  ...

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