title: Import js file from node module with React
body: <p>I try to add the <strong>geojson npm package</strong> <a href="https://www.npmjs.com/package/@mapbox/togeojson" rel="nofollow noreferrer">@mapbox/togeojson</a>.
  But i can not use it in my <strong>React app</strong>. I'm a React/Node beginner, sorry!
  First, i ran <code>npm install --save togeojson</code> to install the module and it's well install in <code>node_module</code> folder.
  Then, in the React module i try to import geojson.</p>
  
  <pre><code>import togeojson from '@mapbox/togeojson';
  </code></pre>
  
  <p>And use it:</p>
  
  <pre><code>console.log(togeojson); //undefined
  var geoJSON = toGeoJSON.gpx(e.target.result);
  </code></pre>