title: react-router: how to get the previous route in onEnter handler?
body: <p>I'm trying to find a way to read the previous route/path when a user hits a new one, within the <code>onEnter</code> handler.</p>
  
  <p>I have a React Router structured like so:</p>
  
  <pre><code>    &lt;Router history={history}&gt;
        &lt;div className="index"&gt;
          &lt;Route
            path="/"
            component={ComposedAppComponent}
            onEnter={this.onEnterHandler.bind(this)}
          &gt;
            &lt;Route name="streamKey" path=":streamKey"&gt;
              &lt;Route name="articleUri" path="(**)" /&gt;
            &lt;/Route&gt;
          &lt;/Route&gt;
        &lt;/div&gt;
      &lt;/Router&gt;
  </code></pre>
  
  <p>the function, <code>onEnterHandler</code>, looks like so:</p>
  
  <pre><code>  onEnterHandler(nextRouteState) {
      const { streamKey, splat } = nextRouteState.params;
  
      const nextPath = `/${streamKey}/${splat}`;
      const prevPath = // HOW DO I GET THE PREVIOUS PATH?
    }
  </code></pre>
  
  <p>I can't seem to find a way to read the previous route path the user was on... I need to make a comparison between the new route and previous one. Any input on how to approach this is much appreciated. :) </p>
  
  <p>Cheers!</p>