JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://openlayers.org/api/OpenLayers.js"></script>
<body>
    <div id="map" style="height: 500px"></div>
</body>

JavaScript

// See the error last line of the script

// Bearing computation is ok (try drawing two points on the map, and see console output


    OpenLayers.Handler.Path.prototype.addPointByLonLat = function(lonlat) {
        this.layer.removeFeatures([this.point]);
        this.point = new OpenLayers.Feature.Vector(
                new OpenLayers.Geometry.Point(lonlat.lon, lonlat.lat)
        );
        this.line.geometry.addComponent(
                this.point.geometry, this.line.geometry.components.length
        );
        this.layer.addFeatures([this.point]);
        this.callback("point", [this.point.geometry, this.getGeometry()]);
        this.callback("modify", [this.point.geometry, this.getSketch()]);
        this.drawFeature();
        delete this.redoStack;
    };




 var CONSTANTS = {
     MAP_FROM_PROJECTION: new OpenLayers.Projection("EPSG:4326"), // Transform from WGS 1984
     MAP_TO_PROJECTION: new OpenLayers.Projection("EPSG:900913") // to Spherical Mercator Projection
 };

 function radians(n) {
     return n * (Math.PI / 180);
 }

 function degrees(n) {
     return n * (180 / Math.PI);
 }


 function computeBearing(startLat, startLong, endLat, endLong) {
     startLat = radians(startLat);
     startLong = radians(startLong);
     endLat = radians(endLat);
     endLong = radians(endLong);

     var dLong = endLong - startLong;

     var dPhi = Math.log(Math.tan(endLat / 2.0 + Math.PI / 4.0) / Math.tan(startLat / 2.0 + Math.PI / 4.0));
     if (Math.abs(dLong) > Math.PI) {
         if (dLong > 0.0) dLong = -(2.0 * Math.PI - dLong);
         else dLong = (2.0 * Math.PI + dLong);
     }

     return (degrees(Math.atan2(dLong, dPhi)) + 360.0) % 360.0;
 }


 map = new OpenLayers.Map("map");
 map.addLayer(new OpenLayers.Layer.OSM());
 map.setCenter(new OpenLayers.LonLat(3, 47).transform(CONSTANTS.MAP_FROM_PROJECTION, CONSTANTS.MAP_TO_PROJECTION), 6);


 var lineLayer = new OpenLayers.Layer.Vector("Line Layer");

 map.addLayers([lineLayer]);

 var lineControl...