Accepting properties to make a plugin configurable for users

reearth.yml

id: test
name: test
version: 1.0.0
extensions:
  - id: map
    type: block
    name: Map
    schema:
      groups:
        - id: default
          fields:
            - id: location
              type: latlng
              title: Location

map.js

const html = `
  <link rel="stylesheet" href="https://unpkg.com/leaflet@1.7.1/dist/leaflet.css" />
  <script id="l" src="https://unpkg.com/leaflet@1.7.1/dist/leaflet.js"></script>
  <div id="map" style="width: 100%; height: 300px;"></div>
  <script>
      document.getElementById("l").addEventListener("load", () => {
        const map = L.map("map").setView([0, 0], 13);
        L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
          attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
        }).addTo(map);

        const marker = L.marker();

        const cb = (block) => {
          if (block && block.property && block.property.default && block.property.default.location) {
            const latlng = [
              block.property.default.location.lat,
              block.property.default.location.lng
            ];
            map.setView(latlng);
            marker.setLatLng(latlng).addTo(map);
          } else {
            marker.remove();
          }
        };

        addEventListener("message", e => {
          if (e.source !== parent || !e.data.block) return;
          cb(e.data);
        });

        cb(${JSON.stringify(reearth.block)});
      });
    </script>
`;

reearth.ui.show(html);

reearth.on("update", () => {
  reearth.ui.postMessage({
        block: reearth.block
    });
});

Then install this plugin, add a map widget, and select it. You'll see the properties of the map block on the left panel.

Type location, and then a marker will be put on the leaflet map.

For details of plugin manifest, refer to Manifest reference.