Use template engine to render the map.

src/Bundle/Resources/config/services.yml

@@ -16,6 +16,7 @@ services:
       - '@netzmacht.contao_leaflet.cache'
       - '@netzmacht.contao_leaflet.frontend.data_controller'
       - '@netzmacht.contao_toolkit.repository_manager'
+      - '@templating'
 
   netzmacht.contao_leaflet.libraries:
     class: Netzmacht\Contao\Leaflet\Frontend\Assets\LibrariesConfiguration

src/Bundle/Resources/contao/templates/leaflet_map_html.html5

@@ -1,6 +1,7 @@
-<div id="<?php echo $mapId; ?>" style="<?php echo $style; ?>"></div>
+<div id="<?= $this->mapId ?>" style="<?= $this->style ?>"></div>
 <script>
-    L.contao.addMap('<?php echo $mapId; ?>', function () {
-        <?php echo $javascript; ?>
+    L.contao.addMap('<?= $this->mapId ?>', function () {
+        <?= $this->javascript ?>
         return {map: map, layers: layers, controls: controls, icons: icons};
-    }());</script>
+    }());
+</script>

src/Bundle/Resources/contao/templates/leaflet_map_js.html5

@@ -1,5 +1,5 @@
-L.contao.addMap('<?php echo $mapId; ?>', function() {
-<?php echo $javascript; ?>
+L.contao.addMap('<?= $this->mapId ?>', function() {
+<?= $this->javascript ?>
 
 return { map: map, layers: layers, controls: controls, icons: icons };
 }());