Component imported in another component is not showing - Reactjs - reactjs

Question

Hi just started to learn basics of React and have problem with rendering my component in another component.
<Header> component imported in index.js is not showing.
Index.js:
import React, {Component} from 'react';
import { render } from 'react-dom';
import Header from './components/Header';
import Home from './components/Home';
class App extends Component{
render(){
return(
<div className="container">
<div className="row">
<div className="col-xs-10 col-xs-offset-1">
<div className="col-xs-10 col-xs-offset-1">
<Header />
</div>
</div>
</div>
<div className="row">
<div className="col-xs-10 col-xs-offset-1">
</div>
</div>
</div>
);
}
}
render(<App />, window.document.getElementById('container'));
I have this error:
Error: Minified React error #130; visit http://reactjs.org/docs/error-decoder.html?invariant=130&args[]=undefined&args[]= for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
Header.js component also:
import React from "react";
export class Header extends React.Component {
render() {
return (
<nav className="navbar navbar-default">
<div className="container">
<div className="navbar-header">
<ul className="nav navbar-nav">
<li>Home</li>
</ul>
</div>
</div>
</nav>
);
}
}

Answer 1

When you open up the URL it says:
Element type is invalid: expected a string (for built-in components)
or a class/function (for composite components) but got: undefined.
Which means:
you forgot to import Header in a file
you import it incorrect way,
Header is not exported in a file
all of the above
After your edit:
You need to fix export (like I wrote above) to:
export default class Header extends React.Component {
you miss the default.

Answer 2

import React from "react";
export default class Header extends React.Component {
render() {
return (
<nav className="navbar navbar-default">
<div className="container">
<div className="navbar-header">
<ul className="nav navbar-nav">
<li>Home</li>
</ul>
</div>
</div>
</nav>
);
}
}
Use the default keyword while exporting the Header.js
it'll start working fine :)