title: to realize clustering on the GoogleMap
body: <p>How to realize clustering of markers on the map? Help me clear errors. necessary scripts are connected. Error:   <a href="https://i.stack.imgur.com/qMz8B.png" rel="nofollow noreferrer">enter image description here</a>
  <div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>function CustomMarker(latlng, map, imageSrc) {
      this.latlng_ = latlng;
      this.imageSrc = imageSrc;
      this.setMap(map);
  }
  CustomMarker.prototype = new google.maps.OverlayView();
     ...
  
  var map = new google.maps.Map(document.getElementById("map"), {
      zoom: 17,
      center: new google.maps.LatLng(48.42216, 44.31308),
      mapTypeId: google.maps.MapTypeId.ROADMAP
  });
  var data = [{
      profileImage: "./images/1.jpg",
      pos: [48.42217, 44.31308]
  }, {
      profileImage: "./images/2.jpg",
      pos: [48.42220, 44.31308]
  }];
  for(var i=0;i&lt;data.length;i++){
      new CustomMarker(new google.maps.LatLng(data[i].pos[0],data[i].pos[1]), map,  data[i].profileImage)
  }
  var markerCluster = new MarkerClusterer(map, data,
      {imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m'});</code></pre>
  </div>
  </div>
  </p>