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[英]Issue with “TypeError: Class extends value undefined is not a constructor or null” in React Class
[英]TypeError: Class extends value undefined is not a constructor or null (React Meteor Data)
将React Meteor数据添加到我的Meteor项目中时出现错误。
我只是在他们的网站上做他们的Todo List App教程。
这是我得到的错误:
TypeError: Class extends value undefined is not a constructor or null
at ReactMeteorData.jsx (packages/react-meteor-data/ReactMeteorData.jsx:162:36)
at fileEvaluate (packages\modules-runtime.js:339:7)
at require (packages\modules-runtime.js:238:16)
at createContainer.jsx (packages/react-meteor-data/createContainer.jsx:1:210)
at fileEvaluate (packages\modules-runtime.js:339:7)
at require (packages\modules-runtime.js:238:16)
at react-meteor-data.jsx (packages/react-meteor-data/react-meteor-data.jsx:1:139)
at fileEvaluate (packages\modules-runtime.js:339:7)
at require (packages\modules-runtime.js:238:16)
at C:\simple-todos\.meteor\local\build\programs\server\packages\react-meteor-data.js:330:15
at C:\simple-todos\.meteor\local\build\programs\server\packages\react-meteor-data.js:337:3
at C:\simple-todos\.meteor\local\build\programs\server\boot.js:411:36
at Array.forEach (<anonymous>)
at C:\simple-todos\.meteor\local\build\programs\server\boot.js:220:19
at C:\simple-todos\.meteor\local\build\programs\server\boot.js:471:5
at Function.run (C:\simple-todos\.meteor\local\build\programs\server\profile.js:510:12)
Exited with code: 1
Your application is crashing. Waiting for file change.
有谁知道为什么会这样? 这是我导入react-meteor-data的文件:
import React, { Component } from 'react';
import { withTracker } from 'meteor/react-meteor-data';
import { Tasks } from '../api/tasks.js';
import Task from './Task.js';
// App component - represents the whole app
class App extends Component {
renderTasks() {
return this.props.tasks.map((task) => (
<Task key={task._id} task={task} />
));
}
render() {
return (
<div className="container">
<header>
<h1>Todo List</h1>
</header>
<ul>
{this.renderTasks()}
</ul>
</div>
);
}
}
export default withTracker(() => {
return {
tasks: Tasks.find({}).fetch(),
};
})(App);
我对MEAN Stack真的很陌生,因此如果我做的很蠢,我深表歉意。
我也遇到过同样的问题。 如果重新启动流星服务器,它将正常工作。
尝试从导入中删除“ .js”。
...
import { Tasks } from '../api/tasks';
import Task from './Task';
...
我重新启动了流星实例。 错误随后消失了。
我在React Meteor To-Do列表教程的步骤3.4上遇到了此错误。
我文件中的导入包含完全限定的名称,如下所示:
import { Tasks } from '../api/tasks.js';
import Task from './Task.js';
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