Add a start and end marker on the map about activities

[Djailla]

I did try this, but it failed to clear markers after changing activity

    displayPolyline: function(polyline) {
        if (this.track) {
            this.track.remove();
            this.track = null;
        }
        if (polyline !== null && polyline !== '') {
            const decoded = L.PolylineUtil.decode(polyline);
            this.track = L.polyline(decoded, {color: 'red'}).addTo(this.map);

            var latlngs = this.track.getLatLngs();
            var start = latlngs[0];
            var end = latlngs[latlngs.length - 1];

            L.marker([start.lat, start.lng]).addTo(this.map);
            L.marker([end.lat, end.lng]).addTo(this.map);
            this.map.fitBounds(this.track.getBounds());
        }
    },

[flopp]

You probably need to store the markers (this.start = L.marker(...); this.end = ...) and remove them at the beginning of displayPolyline (this.start.remove(); ...) just like what's done with this.track.

I can implement this tonight.