JSFiddle - React, Tailwind, and code Playground

HTML

<title>Map Demo</title>	
<script src="http://maps.googleapis.com/maps/api/js?sensor=false"></script>
<body>
	<div id="container">
		<div id="map-canvas" style="height: 600px; width: 800px;"></div>
	</div>
</body>

JavaScript

var mapOptions = {
    center: new google.maps.LatLng(0, -0),
    zoom: 4,
    mapTypeId: google.maps.MapTypeId.ROADMAP
};

var map = new google.maps.Map(document.getElementById('map-canvas'),mapOptions);

// to get the pixel position from the latlng
// http://stackoverflow.com/questions/1538681/how-to-call-fromlatlngtodivpixel-in-google-maps-api-v3
var overlay = new google.maps.OverlayView();
overlay.draw = function() {};
overlay.setMap(map);

google.maps.event.addListenerOnce(map, 'idle', function() {
    if (overlay.getProjection()) {
        var points = [
            { latlng: new google.maps.LatLng(40, -100), title: '1' },
            { latlng: new google.maps.LatLng(40.125, -100.125), title: '2' },
            { latlng: new google.maps.LatLng(40.25, -100.25), title: '3' },
            { latlng: new google.maps.LatLng(40.5, -100.5), title: '4' },
            { latlng: new google.maps.LatLng(40.75, -100.75), title: '5' },
            { latlng: new google.maps.LatLng(41, -101), title: '6' },
            { latlng: new google.maps.LatLng(35, -95), title: '7' },
            { latlng: new google.maps.LatLng(45, 105), title: '8' },
            { latlng: new google.maps.LatLng(25, -115), title: '9' },
            { latlng: new google.maps.LatLng(55, -85), title: '10' },
            { latlng: new google.maps.LatLng(30, -34), title: '11' }
        ];
        
        // for each point			
        var markers = [];
        points.forEach(function (point) {
            var nearby = false;
            var pointPixelPosition =  overlay.getProjection().fromLatLngToContainerPixel(point.latlng);
            markers.forEach(function(marker) {
                var markerPixelPosition = overlay.getProjection().fromLatLngToContainerPixel(marker.getPosition());
                // check for marker 'near by'
                if (Math.abs(pointPixelPosition.x - markerPixelPosition.x) < 10 || Math.abs(pointPixelPosition.y - markerPixelPosition.y) < 10) {
                    nearby =...