我得到这个错误:
Uncaught Error: Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object.
这是我的代码:
var React = require('react')
var ReactDOM = require('react-dom')
var Router = require('react-router')
var Route = Router.Route
var Link = Router.Link
var App = React.createClass({
render() {
return (
<div>
<h1>App</h1>
<ul>
<li><Link to="/about">About</Link></li>
</ul>
</div>
)
}
})
var About = require('./components/Home')
ReactDOM.render((
<Router>
<Route path="/" component={App}>
<Route path="about" component={About} />
</Route>
</Router>
), document.body)
我的家。jsx文件:
var React = require('react');
var RaisedButton = require('material-ui/lib/raised-button');
var Home = React.createClass({
render:function() {
return (
<RaisedButton label="Default" />
);
},
});
module.exports = Home;
除了进口/出口问题提到。我发现使用React.cloneElement()向子元素添加道具，然后渲染它给了我同样的错误。
我不得不改变:
render() {
const ChildWithProps = React.cloneElement(
this.props.children,
{ className: `${PREFIX}-anchor` }
);
return (
<div>
<ChildWithProps />
...
</div>
);
}
to:
render() {
...
return (
<div>
<ChildWithProps.type {...ChildWithProps.props} />
</div>
);
}
有关更多信息，请参阅React.cloneElement()文档。
我也遇到了同样的问题，并意识到我在JSX标记中提供了一个未定义的React组件。问题是要渲染的react组件是动态计算的，它最终没有定义!
错误说明:
不变性违反:元素类型无效:期望为字符串(对于内置组件)或类/函数(对于复合组件)，但得到:undefined。您可能忘记从定义组件的文件中导出组件。检查C.的渲染方法，
产生此错误的示例:
var componentA = require('./components/A');
var componentB = require('./components/B');
const templates = {
a_type: componentA,
b_type: componentB
}
class C extends React.Component {
constructor(props) {
super(props);
}
// ...
render() {
//Let´s say that depending on the uiType coming in a data field you end up rendering a component A or B (as part of C)
const ComponentTemplate = templates[this.props.data.uiType];
return <ComponentTemplate></ComponentTemplate>
}
// ...
}
问题是提供了一个无效的“uiType”，因此产生了未定义的结果:
模板['无效字符串']
就我而言，
//details.js
import React from 'react'
const Details = (props) =>{
return <h1>Details</h1>
}
export default Details;
//main.js
import React from "react";
import { withRouter } from "react-router";
import {Route,BrowserRouter as Router,Redirect,Switch,Link} from "react-router-dom";
import Details from "./myAccount/details";
const Main = (props) => {
return (
<>
<Switch>
<Route path="/my-account/details" component={<Details />} />
</Switch>
</>
);
};
export default withRouter(Main);
===========================
Replaced with below one, error got fixed
component={<Details />} with component={Details}
除了进口/出口问题提到。我发现使用React.cloneElement()向子元素添加道具，然后渲染它给了我同样的错误。
我不得不改变:
render() {
const ChildWithProps = React.cloneElement(
this.props.children,
{ className: `${PREFIX}-anchor` }
);
return (
<div>
<ChildWithProps />
...
</div>
);
}
to:
render() {
...
return (
<div>
<ChildWithProps.type {...ChildWithProps.props} />
</div>
);
}
有关更多信息，请参阅React.cloneElement()文档。
