fix: add last_object_clicked_count to detect repeated marker clicks (#319)

* fix: add last_object_clicked_count to detect repeated marker clicks

Adds a new last_object_clicked_count field that increments on every
layer click. This lets apps detect when the same marker is clicked
multiple times, which was previously impossible because the lat/lng
guard only forwarded changes.

Fixes #316

* fix: split fused test_last_object_clicked_count/test_geojson_styles

test_last_object_clicked_count was accidentally inserted directly in
front of test_geojson_styles with no function boundary, fusing the two
and silently deleting test_geojson_styles as standalone regression
coverage. Split them back into separate top-level functions.

Also drop six noqa: PLC0415 comments from the new test_package.py
tests that ruff (pinned via pre-commit) flags as unused-noqa (RUF100),
since PLC0415 isn't enabled at that ruff version; every other
function-local import in this test suite already omits the noqa.

Author: pctablet505

examples/pages/last_clicked_count.py

@@ -0,0 +1,37 @@
+import streamlit as st
+
+st.set_page_config(
+    page_title="streamlit-folium documentation: Last Clicked Count",
+    page_icon="🔢",
+    layout="wide",
+)
+
+"""
+# streamlit-folium: Last Clicked Count
+
+`last_object_clicked_count` increments every time a marker or drawing is clicked,
+so app code can detect repeated clicks on the same object even when the lat/lng
+has not changed.
+"""
+
+with st.echo(code_location="below"):
+    import folium
+    import streamlit as st
+
+    from streamlit_folium import st_folium
+
+    m = folium.Map(location=[39.949610, -75.150282], zoom_start=13)
+
+    folium.Marker(
+        [39.949610, -75.150282], popup="Liberty Bell", tooltip="Liberty Bell"
+    ).add_to(m)
+
+    output = st_folium(
+        m,
+        width=700,
+        height=500,
+        returned_objects=["last_object_clicked", "last_object_clicked_count"],
+    )
+
+    st.write(output)
+    st.write(f"Click count: {output.get('last_object_clicked_count')}")

streamlit_folium/__init__.py

@@ -346,6 +346,7 @@ def bounds_to_dict(bounds_list: list[list[float]]) -> dict[str, dict[str, float]
     _defaults = {
         "last_clicked": None,
         "last_object_clicked": None,
+        "last_object_clicked_count": None,
         "last_object_clicked_tooltip": None,
         "last_object_clicked_popup": None,
         "all_drawings": None,

streamlit_folium/frontend/src/index.tsx

@@ -14,6 +14,7 @@ var ignore_render = false;
 type GlobalData = {
   lat_lng_clicked: any
   last_object_clicked: any
+  last_object_clicked_count: number
   last_object_clicked_tooltip: string | null
   last_object_clicked_popup: string | null
   last_active_drawing: any
@@ -94,6 +95,7 @@ function updateComponentValue(map: any) {
   let _data = {
     last_clicked: wrapLatLng(global_data.lat_lng_clicked),
     last_object_clicked: wrapLatLng(global_data.last_object_clicked),
+    last_object_clicked_count: global_data.last_object_clicked_count,
     last_object_clicked_tooltip: global_data.last_object_clicked_tooltip,
     last_object_clicked_popup: global_data.last_object_clicked_popup,
     all_drawings: global_data.all_drawings,
@@ -200,6 +202,7 @@ function addLayer(e: any) {
 function onLayerClick(e: any) {
   const global_data = window.__GLOBAL_DATA__
   global_data.last_object_clicked = e.latlng || null
+  global_data.last_object_clicked_count += 1
 
   // Extract tooltip text, guarding against layers that don't fully implement
   // the Leaflet Layer interface (e.g. geocoder result markers).
@@ -493,6 +496,7 @@ async function onRender(event: Event) {
       window.__GLOBAL_DATA__ = {
         lat_lng_clicked: null,
         last_object_clicked: null,
+        last_object_clicked_count: 0,
         last_object_clicked_tooltip: null,
         last_object_clicked_popup: null,
         all_drawings: null,

tests/test_frontend.py

@@ -266,6 +266,26 @@ def test_responsiveness(page: Page):
     page.set_viewport_size({"width": 2000, "height": 2000})
 
 
+def test_last_object_clicked_count(page: Page):
+    page.get_by_role("link", name="last clicked count").click()
+    page.get_by_role("link", name="last clicked count").click()
+
+    expect(page).to_have_title("streamlit-folium documentation: Last Clicked Count")
+
+    # Initial state: count is 0 before any click (frontend initializes it)
+    expect(page.get_by_text('"last_object_clicked_count":0')).to_be_visible()
+
+    # Click the marker
+    click_button_or_marker(page)
+
+    # After one click, count should be 1
+    expect(page.get_by_text('"last_object_clicked_count":1')).to_be_visible()
+
+    # Click the same marker again; lat/lng does not change, but count should increment
+    click_button_or_marker(page)
+    expect(page.get_by_text('"last_object_clicked_count":2')).to_be_visible()
+
+
 def test_geojson_styles(page: Page):
     page.get_by_role("link", name="geojson styles").click()
     page.get_by_role("link", name="geojson styles").click()

tests/test_package.py

@@ -117,3 +117,48 @@ def test_vector_grid():
     VectorGridProtobuf(url, "test").add_to(m)
     leaflet = _get_map_string(m)
     assert "var vector_grid_protobuf_div_1 = L.vectorGrid.protobuf(" in leaflet
+
+
+def test_last_object_clicked_count_default():
+    import folium
+
+    import streamlit_folium as sf
+    from streamlit_folium import st_folium
+
+    original_component_func = sf._component_func
+    captured: dict = {}
+
+    def fake_component_func(**kwargs):
+        captured.update(kwargs)
+        return kwargs.get("default", {})
+
+    try:
+        sf._component_func = fake_component_func
+        m = folium.Map(location=[0, 0], zoom_start=1)
+        result = st_folium(m, returned_objects=["last_object_clicked_count"])
+        assert result["last_object_clicked_count"] is None
+        assert "last_object_clicked_count" in captured.get("default", {})
+    finally:
+        sf._component_func = original_component_func
+
+
+def test_last_object_clicked_count_not_in_default_when_not_requested():
+    import folium
+
+    import streamlit_folium as sf
+    from streamlit_folium import st_folium
+
+    original_component_func = sf._component_func
+    captured: dict = {}
+
+    def fake_component_func(**kwargs):
+        captured.update(kwargs)
+        return kwargs.get("default", {})
+
+    try:
+        sf._component_func = fake_component_func
+        m = folium.Map(location=[0, 0], zoom_start=1)
+        result = st_folium(m, returned_objects=["last_object_clicked"])
+        assert "last_object_clicked_count" not in result
+    finally:
+        sf._component_func = original_component_func