title: React-router: TypeError: Cannot set property 'props' of undefined
body: <p>I am trying to set up routing in <code>Meteor</code> using <code>react-router</code> package and have encountered the following <strong><code>TypeError</code></strong>:</p>
  
  <p>Link to image: <a href="https://postimg.org/image/v0twphnc7/" rel="noreferrer">https://postimg.org/image/v0twphnc7/</a></p>
  
  <p>The code in I use in <code>main.js</code></p>
  
  <pre><code>import React from 'react';
  import ReactDOM from 'react-dom';
  import { Router, Route, IndexRoute, browserHistory } from 'react-router';
  
  // Importing components
  import App from './components/app';
  import Portfolio from './components/portfolio/portfolio';
  
  
  //Creating a route
  const routes = (
    &lt;Router history={browserHistory}&gt;
      &lt;Route path='/' component={App}&gt;
        &lt;Router path='portfolio' component={Portfolio} /&gt;
      &lt;/Route&gt;
    &lt;/Router&gt;
  );
  
  
  // Loading routes
  Meteor.startup(() =&gt; {
    ReactDOM.render(routes, document.querySelector('.universe'));
  });
  </code></pre>
  
  <p>The problem that I've managed to identify is that when I define portfolio as a Simple Component it works.</p>
  
  <pre><code>const Portfolio = () =&gt; {
      return (
          &lt;div className='red'&gt;Portfolio page&lt;/div&gt;
      );
  }
  </code></pre>
  
  <p>But when I extend it from the Component is where the error comes in:</p>
  
  <pre><code>class Portfolio extends Component () {
    render() {
      return (
          &lt;div&gt;Portfolio page&lt;/div&gt;
      );
    }
  }
  </code></pre>
  
  <p><br> Can you please explain the possible difference between "normal" and class component and why the following error appears.</p>