反应。类型无效——期望为字符串

尝试得到react-router (v4.0.0)和react-hot loader (3.0.0-beta.6)很好地发挥，但在浏览器控制台得到以下错误:

Warning: React.createElement: type is invalid -- expected a string
(for built-in components) or a class/function (for composite
components) but got: undefined. You likely forgot to export your
component from the file it's defined in.

index.js:

import React from 'react';
import ReactDom from 'react-dom';
import routes from './routes.js';
require('jquery');
import 'bootstrap/dist/css/bootstrap.min.css';
import 'bootstrap/dist/js/bootstrap.min.js';
import './css/main.css';

const renderApp = (appRoutes) => {
    ReactDom.render(appRoutes, document.getElementById('root'));
};

renderApp( routes() );

routes.js:

import React from 'react';
import { AppContainer } from 'react-hot-loader';
import { Router, Route, browserHistory, IndexRoute } from 'react-router';
import store from './store/store.js';
import { Provider } from 'react-redux';
import App from './containers/App.jsx';
import Products from './containers/shop/Products.jsx';
import Basket from './containers/shop/Basket.jsx';

const routes = () => (

    <AppContainer>
        <Provider store={store}>
            <Router history={browserHistory}>
                <Route path="/" component={App}>
                    <IndexRoute component={Products} />
                    <Route path="/basket" component={Basket} />
                </Route>
            </Router>
        </Provider>
    </AppContainer>

);

export default routes;

当前回答

我所缺少的是我正在使用

import { Router, Route, browserHistory, IndexRoute } from 'react-router';

正确答案应该是:

import { BrowserRouter as Router, Route } from 'react-router-dom';

当然你需要添加npm包react-router-dom:

npm install react-router-dom@next --save

2017-08-01 11:21:35

其他回答

在我的例子中，创建组件和渲染的顺序很重要。我在创建组件之前渲染了它。最好的方法是创建子组件，然后是父组件，然后呈现父组件。改变顺序为我解决了这个问题。

2018-06-15 14:59:14

// @flow

import React from 'react';
import { styleLocal } from './styles';
import {
  View,
  Text,
  TextInput,
  Image,
} from 'react-native';
import { TouchableOpacity } from 'react-native-gesture-handler';

export default React.forwardRef((props, ref) => {
const { onSeachClick, onChangeTextSearch , ...otherProps } = props;

  return (
        <View style={styleLocal.sectionStyle}>
        <TouchableOpacity onPress={onSeachClick}>
            <Image                              
                    source={require('../../assets/imgs/search.png')}
                    style={styleLocal.imageStyle} />
                </TouchableOpacity>
            <TextInput
                style={{ flex: 1, fontSize: 18 }}
                placeholder="Search Here"
                underlineColorAndroid="transparent"
                onChangeText={(text) => { onChangeTextSearch(text) }}
            />
        </View>
  );
});
 import IGPSSearch from '../../components/IGPSSearch';
<Search onSeachClick={onSeachClick} onChangeTextSearch= {onChangeTextSearch}> </Search>

2021-02-03 20:05:14

当我将nothingundefined作为值传递给我创建的子组件时，发生了这个问题。我做了这个<MyComponent src="" />导致错误。然后将其更改为<MyComponent src=" " />，因为我真的不想传递任何东西…问题解决了。

2022-03-18 15:50:56

大多数情况下，这表示导入/导出错误。但是要注意，不仅要确保堆栈跟踪中引用的文件本身得到了良好的导出，还要确保该文件正确地导入了其他组件。在我的例子中，错误是这样的:

import React from //注意末尾的.css，这是错误的原因! import SeeminglyUnimportantComponent from './SeeminglyUnimportantComponent.css'; Const组件= (props) => ( < div > < SeeminglyUnimportantComponent / > {/ *……这里的组件代码*/} < / div > ）; 导出默认组件;

2019-06-28 23:05:57

当我在我的渲染/返回语句中有一个糟糕的引用时，这个问题出现在我身上。(指向不存在的类)。还要检查return语句代码中的错误引用。

2019-05-05 12:29:44

反应。类型无效——期望为字符串

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