Calculate geo position based on arbitary distance in LineString

HTML

<script src="https://heremaps.github.io/maps-api-for-javascript-examples/test-credentials.js"></script>
<!DOCTYPE html>
<html>
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    <title>Calculate geo position based on arbitary distance in LineString</title>
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    <link rel="stylesheet" type="text/css" href="demo.css" />
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  </head>
  <body id="markers-on-the-map">
    <div class="page-header">
        <h4>Calculate geo position based on arbitary distance in LineString</h4>
    </div>
    <div id="map"></div>
  </body>
</html>

CSS

#map {
    width: 95%;
    height: 400px;
    background: grey;
}

#panel {
    width: 100%;
    height: 400px;
}

JavaScript

getDistancePosition = function(lineString, distanceTreshold) {
	let latLngAlts = lineString.getLatLngAltArray(),
		previousDistance = 0;
		distance = 0;

    // each geo point in latLngAlts array is represented as lat, lng, alt 
    // therefore we need to increase counter by 3 for each loop cycle (we ignore alt values)
	for (let i = 0; i < latLngAlts.length - 5; i = i+3) {
		let point1 = new H.geo.Point(latLngAlts[i], latLngAlts[i + 1]),
				point2 = new H.geo.Point(latLngAlts[i + 3], latLngAlts[i + 4]);
		
    distance += point1.distance(point2);
        
		if (distance >= distanceTreshold) {
    	// calculate angle between two geographical points
      // used answer from https://stackoverflow.com/questions/3809179/angle-between-2-gps-coordinates
			let dy = point2.lat - point1.lat,
				dx = Math.cos(Math.PI/180*point1.lat)*(point2.lng - point1.lng),
				angle = Math.atan2(dy, dx)*180/Math.PI,
				bearing = 90 - angle,
				remainingDistance = distanceTreshold - previousDistance;
            
      // create geo point based on angle and remainingDistance
			distancePoint = point1.walk(bearing, remainingDistance);

      // return the calculated geo point 
			/* alert('Result is in distance of ' + Math.round(remainingDistance) +  ' meters from point ' + i/3) */;
      return distancePoint;
		} else {
			previousDistance = distance;
		}
	}
	
    alert('could not find the distance in provided LineString (max distance: ' + distance + ')');
    return null; 
}

// create map
var platform = new H.service.Platform({
  apikey: window.apikey
}),
	defaultLayers = platform.createDefaultLayers(),
	map = new H.Map(document.getElementById('map'),
    defaultLayers.vector.normal.map,{
    center: {lat:52.5159, lng:13.3777},
    zoom: 14,
    pixelRatio: window.devicePixelRatio || 1
  }),
  behavior = new H.mapevents.Behavior(new H.mapevents.MapEvents(map)),
	ui = H.ui.UI.createDefault(map, defaultLayers),
  lineString,
  polyline;

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