maptalks - New control

New control
index.html
<!DOCTYPE html>
<html>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Plugin development - New control</title>
  <style type="text/css">
    html,body{margin:0px;height:100%;width:100%}
    .container{width:100%;height:100%}
    .my-control{background:#051127;border:5px solid #fff;border-radius:5px;color:#fff;height:50px;line-height:50px;text-align:center;font-size:30px;padding:0 8px}
  </style>
  <link rel="stylesheet" href="https://unpkg.com/maptalks/dist/maptalks.css">
  <script type="text/javascript" src="https://unpkg.com/maptalks/dist/maptalks.min.js"></script>
  <body>

    <div id="map" class="container"></div>
    <script>
      const options = {
        'position' : 'top-right',
        'content'  : 'My Control'
      };

      class MyControl extends maptalks.control.Control {
        buildOn(map) {
          var dom = maptalks.DomUtil.createEl('div', 'my-control');
          dom.innerText = this.options['content'];
          return dom;
        }
      }

      MyControl.mergeOptions(options);

      var map = new maptalks.Map('map', {
        center: [-0.113049,51.498568],
        zoom: 14,
        baseLayer: new maptalks.TileLayer('base', {
          urlTemplate: 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png',
          subdomains: ["a","b","c","d"],
          attribution: '&copy; <a href="http://osm.org">OpenStreetMap</a> contributors, &copy; <a href="https://carto.com/">CARTO</a>'
        })
      });

      var control = new MyControl({
        'content'   : 'Hello, MyControl!'
      });
      map.addControl(control);

    </script>
  </body>
</html>