title: can't access 'coordinates' member of geojson feature collection
body: <p>I have a GeoJSON feature collection in my Angular app that is an array of features, each containing a geometry object and properties object. Structure looks like this:</p>
  
  <pre><code>import { FeatureCollection, Feature } from 'geojson';
  
  staticBreadcrumbs: GeoJSON.FeatureCollection&lt;GeoJSON.Geometry&gt;;
  
  this.staticBreadcrumbs = {
      type : 'FeatureCollection',
      features: [
      {
          type: 'Feature',
          properties: {
              property1:  'property1',
              property2:  'property2'
          },
          geometry: {
              type: 'Point',
              coordinates: [-117.14024305343628, 32.81294345855713]
          }
      },
      {
          type: 'Feature',
          properties: {
          ...
  </code></pre>
  
  <p>I'm trying to create a mapboxgl marker for each feature in the collection and need to get the coordinates from each GeoJSON object, the compiler is telling me that the coordinates aren't part of the feature. The specific error is: Property 'coordinates' does not exist on type 'Geometry'. Property 'coordinates' does not exist on type 'GeometryCollection'.</p>
  
  <pre><code>console.log('this.staticBreadcrumbs.features[0]', this.staticBreadcrumbs.features[0]);
  
  var marker = new Marker(el)
      .setLngLat([
          this.staticBreadcrumbs.features[0].geometry.coordinates[0],
          this.staticBreadcrumbs.features[0].geometry.coordinates[1]
      ])
      .addTo(this.map);
  </code></pre>
  
  <p>My console.log displays</p>
  
  <pre><code> this.staticBreadcrumbs.features[0]
   {type: "Feature", properties: {…}, geometry: {…}}
   1.  geometry:
       1.  coordinates: Array(2)
           1.  0: -117.14024305343628
           2.  1: 32.81294345855713
           3.  length: 2
           4.  __proto__: Array(0)
       2.  type: "Point"
     2. __proto__: Object
  2. properties: {deviceID: "CAP498", altitude: 401.6721913312, autonomous: 0, azimuth: 0, batteryStatusLabel: "Nominal", …}
  3. type: "Feature"
  4. __proto__: Object
  </code></pre>
  
  <p>The coordinates are exactly where I expect them to be, but I can't get to them. I have tried all sort of different ways to declare the Feature collection, but I can't find the right combination.</p>
  
  <p>What do I need to do in order to access the coordinates?</p>
  
  <p>Thanks.....</p>