Update FeatureLayer to dynamically update .layerBounds if initialized

without a options.extent bounds

src/mapml/layers/FeatureLayer.js

@@ -13,6 +13,11 @@ export var FeatureLayer = L.FeatureGroup.extend({
         2. for static templated feature: null
         3. for non-templated feature: layer- (with no src) or mapml file (with src)
       */
+    // options.extent: when you use a FeatureLayer, you can either get it to calculate the
+    // .layerBounds dynamically (the default), based on adds/removes of features from the layer/
+    // or you can construct it with a bounds (via options.extent),
+    // which will then remain static for the lifetime of the layer
+
     L.setOptions(this, options);
     if (this.options.static) {
       this._container = L.DomUtil.create(
@@ -53,7 +58,7 @@ export var FeatureLayer = L.FeatureGroup.extend({
       this.addData(mapml, native.cs, native.zoom);
     } else if (!mapml) {
       this.isVisible = false;
-      this.layerBounds = null;
+      this.layerBounds = this.options.extent ? this.options.extent : null;
       this.zoomBounds = this.options.zoomBounds;
     }
   },
@@ -273,14 +278,16 @@ export var FeatureLayer = L.FeatureGroup.extend({
     }
 
     let layer = this.geometryToLayer(mapml, options, nativeCS, +zoom, title);
-    let ext = mapml.extent,
-      xmin = ext.topLeft.pcrs.horizontal,
-      ymin = ext.bottomRight.pcrs.vertical,
-      xmax = ext.bottomRight.pcrs.horizontal,
-      ymax = ext.topLeft.pcrs.vertical,
-      bnd = L.bounds(L.point(xmin, ymin), L.point(xmax, ymax));
+    if (!this.options.extent) {
+      let ext = mapml.extent,
+        xmin = ext.topLeft.pcrs.horizontal,
+        ymin = ext.bottomRight.pcrs.vertical,
+        xmax = ext.bottomRight.pcrs.horizontal,
+        ymax = ext.topLeft.pcrs.vertical,
+        bnd = L.bounds(L.point(xmin, ymin), L.point(xmax, ymax));
 
-    this.layerBounds = this.layerBounds ? this.layerBounds.extend(bnd) : bnd;
+      this.layerBounds = this.layerBounds ? this.layerBounds.extend(bnd) : bnd;
+    }
     if (layer) {
       // if the layer is being used as a query handler output, it will have
       // a color option set.  Otherwise, copy classes from the feature

src/mapml/layers/MapMLLayer.js

@@ -1515,6 +1515,9 @@ export var MapMLLayer = L.Layer.extend({
           pane: layer._container,
           opacity: layer.options.opacity,
           projection: layer._properties.projection,
+          // by NOT passing options.extent, we are asking the FeatureLayer
+          // to dynamically update its .layerBounds property as features are
+          // added or removed from it
           native: native,
           zoomBounds: M.getZoomBounds(layer._content, native.zoom),
           // each owned child layer gets a reference to the root layer

src/mapml/layers/TemplatedFeaturesLayer.js

@@ -35,6 +35,8 @@ export var TemplatedFeaturesLayer = L.Layer.extend({
         // pass the vector layer the container for the parent into which
         // it will append its own container for rendering into
         pane: container,
+        // the extent will be static, fixed, constant for the lifetime of the layer
+        extent: this.extentBounds,
         opacity: opacity,
         projection: map.options.projection,
         static: true,