Add position to Maps add method (#1156)

* Add position to add method

* Rename position to index

* Add collapsed option to LayerControl

* Actually add ui-test

* Update Playwright Snapshots

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: gjmooney

ipyleaflet/leaflet.py

@@ -1758,11 +1758,17 @@ class LayersControl(Control):
     """LayersControl class, with Control as parent class.
 
     A control which allows hiding/showing different layers on the Map.
+    Attributes
+    ----------------------
+    collapsed: bool, default True
+        Set whether control should be open or closed by default
     """
 
     _view_name = Unicode('LeafletLayersControlView').tag(sync=True)
     _model_name = Unicode('LeafletLayersControlModel').tag(sync=True)
 
+    collapsed = Bool(True).tag(sync=True, o=True)
+
 
 class MeasureControl(Control):
     """MeasureControl class, with Control as parent class.
@@ -2676,23 +2682,31 @@ def __isub__(self, item):
     def __add__(self, item):
         return self.add(item)
 
-    def add(self, item):
+    def add(self, item, index=None):
         """Add an item on the map: either a layer or a control.
 
         Parameters
         ----------
         item: Layer or Control instance
             The layer or control to add.
+        index: int
+            The index to insert a Layer. If not specified, the layer is added to the end (on top).
         """
         if hasattr(item, 'as_leaflet_layer'):
             item = item.as_leaflet_layer()
 
         if isinstance(item, Layer):
             if isinstance(item, dict):
                 item = basemap_to_tiles(item)
+
             if item.model_id in self._layer_ids:
                 raise LayerException('layer already on map: %r' % item)
-            self.layers = tuple([layer for layer in self.layers] + [item])
+            if index is not None:
+                if not isinstance(index, int) or index < 0 or index > len(self.layers):
+                    raise ValueError("Invalid index value")
+                self.layers = tuple(list(self.layers)[:index] + [item] + list(self.layers)[index:])
+            else:
+                self.layers = tuple([layer for layer in self.layers] + [item])
 
         elif isinstance(item, Control):
             if item.model_id in self._control_ids:

ui-tests/notebooks/LayerIndex.ipynb

@@ -0,0 +1,64 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "application/vnd.jupyter.widget-view+json": {
+       "model_id": "01b5fa59850e400c907ab3a552ac4e85",
+       "version_major": 2,
+       "version_minor": 0
+      },
+      "text/plain": [
+       "Map(center=[52.204793, 360.121558], controls=(ZoomControl(options=['position', 'zoom_in_text', 'zoom_in_title'…"
+      ]
+     },
+     "execution_count": 13,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "from ipyleaflet import Map, Marker, LayersControl\n",
+    "\n",
+    "\n",
+    "m = Map(center=(52.204793, 360.121558), zoom=15)\n",
+    "m.add(LayersControl(position='topright', collapsed=False))\n",
+    "marker = Marker(location=(52.204793, 360.121558), draggable=False, name=\"One\")\n",
+    "marker2 = Marker(location=(52.204793, 360.131728), draggable=False, name=\"Two\")\n",
+    "marker3 = Marker(location=(52.204793, 360.111728), draggable=False, name=\"Three\")\n",
+    "\n",
+    "\n",
+    "m.add(marker)\n",
+    "m.add(marker2)\n",
+    "m.add(marker3, index=1)\n",
+    "\n",
+    "m"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.12.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}