Сергей Софьичев

function initMap() {
			var customMapType = new google.maps.StyledMapType([
				{
					stylers: [
						{saturation: -100}
					]
				}
			], {
				name: 'Custom Style'
			});

			var customMapTypeId = 'custom_style';

			var map = new google.maps.Map(document.getElementById('index-map'), {
				zoom: 4,
				center: {lat: 54.794612, lng: 70.7},
				mapTypeControlOptions: {
					mapTypeIds: [google.maps.MapTypeId.ROADMAP, customMapTypeId]
				}
			});

			map.mapTypes.set(customMapTypeId, customMapType);
  			map.setMapTypeId(customMapTypeId);

  			var contentString = '<div>TEST</div>';

			var infowindow = new google.maps.InfoWindow({
				content: contentString,
				maxWidth: 400
			});

			var marker = new google.maps.Marker({
				position: {lat:53, lng: 65},
				map: map,
				icon: '/images/icons/index-marker.png'
			});

			marker.addListener('click', function() {
				infowindow.open(map, marker);
			});

		}
		initMap();