maptalks - Copy map by JSON

Copy map by JSON
index.html
<!DOCTYPE html>
<html>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>JSON Serialization - Copy map by JSON</title>
  <style type="text/css">
    html,body{margin:0px;height:100%;width:100%}
    .container{width:calc(50% - 2px);height:calc(100% - 2px);float:left;border:1px solid}
    #map1{width:calc(50% - 2px);height:calc(100% - 2px);float:right;border:1px solid}
  </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>
    <div id="map1"></div>

    <script>
      var map = new maptalks.Map('map', {
        center: [-0.113049,51.498568],
        zoom: 13,
        attribution: true,
        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>'
        }),
        layers: [
          new maptalks.VectorLayer('v', [new maptalks.Marker([-0.113049,51.498568])])
        ]
      });

      var mapJSON = map.toJSON();
      maptalks.Map.fromJSON('map1', mapJSON);

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