JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mapDiv" style="width: 600px; height: 400px;">
</div>
<script>
    //for using the google map without a key
    window._alert = window.alert;
    window.alert = function() {return;};
</script>
<script src="http://maps.google.com/maps?file=api&amp;v=2&amp;sensor=true&amp;key=AIzaSyC2YxRC0b3AKEHgj7DQ4ghcGmlxU3OaI4k" type="text/javascript"></script>

JavaScript

window.radiusOfEarth = 6371; // km

window.setupMap = function() {
    window.map = new GMap2(document.getElementById("mapDiv"));
    var centerPoint = new GLatLng(37.4419, -122.1419);
    map.setCenter(centerPoint, 8);
    map.addControl(new GLargeMapControl3D());
    map.addControl(new GMapTypeControl());
    
    var marker = new GMarker(centerPoint);
    var markerText = "Center @ 37.4419, -122.1419";
    GEvent.addListener(marker, "click", markerClickHandler(marker, markerText));
    map.addOverlay(marker);
    
    var points = pointsAround(37.4419, -122.1419, 50);
    //_alert(points.length);
    for (var index = 0; index < points.length; index++) {
        var point = points[index];
        var latlng = new GLatLng(point.lat, point.lng);
        marker = new GMarker(latlng);
        markerText = "Marker @ " + point.lat + ", " + point.lng;
        GEvent.addListener(marker, "click", markerClickHandler(marker, markerText));
        map.addOverlay(marker);
    }
};

window.markerClickHandler = function(marker, text) {
    return function() {
        marker.openInfoWindowHtml(text);
    };
};

window.pointsAround = function(centerLat, centerLng, radius, numInterpolations) {
    var result = [];

    //do annoying trig maths to work out the delta in latitude between our start and end points
    var targetD = radius;          //km
    var fractionalDistance = (targetD / radiusOfEarth) / 2;
    var sqrtA = Math.sin(fractionalDistance);
    var a = sqrtA * sqrtA;
    var sinHalfDLat = Math.sqrt(a);
    var dLat = Math.asin(sinHalfDLat) * 2;
    var dLatDegrees = degrees(dLat);
    
    var minLat = centerLat - dLatDegrees;            //furthest valid latitude to the above the origin
    var maxLat = centerLat + dLatDegrees;            //furthest valid latitude to the below the origin
    
    var centerLatRadians = radians(centerLat); 
    
    //topmost and bottommost points in the circle
    result.push({lat: minLat, lng: centerLng});
    result.push({lat:...