title: How to set Google Map's feature ID from geojson?
body: <p>How to set <a href="https://developers.google.com/maps/documentation/javascript/reference#Data.Feature" rel="nofollow noreferrer">Google Map's feature's</a> <code>id</code> from geojson?</p>
  
  <p><code>id</code> is what returned by <code>getId()</code> function.</p>
  
  <p>The following code does not work (prints <code>undefined</code>) although <code>id</code> property exists in properties:</p>
  
  <pre><code>var uluru = {lat: -25.363, lng: 131.044};
    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 4,
      center: uluru
    });
    var data = {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [131.044, -25.363]
      },
      "properties": {
        "Id": 12
      }
    };
    map.data.addGeoJson(data);
    map.data.forEach(function(feature){
      console.log("Id from Google's feature: " + feature.getId());
    });
  </code></pre>
  
  <p>Fiddle: <a href="https://jsfiddle.net/dimskraft/hj2t5je3/5/" rel="nofollow noreferrer">https://jsfiddle.net/dimskraft/hj2t5je3/5/</a></p>
  
  <p><strong>UDPATE</strong></p>
  
  <p>I can write</p>
  
  <pre><code>var data = {
      "type": "Feature",
      "id": 13,
      "geometry": {
        "type": "Point",
        "coordinates": [131.044, -25.363]
      },
  </code></pre>
  
  <p>but won't this be incorrect Geojson?</p>