googlemaps-samples · willum070 · Feb 4, 2026 · Feb 6, 2026 · Feb 6, 2026 · Feb 6, 2026
diff --git a/samples/dds-datasets-polygon-click/README.md b/samples/dds-datasets-polygon-click/README.md
@@ -0,0 +1,41 @@
+# Google Maps JavaScript Sample
+
+## dds-datasets-polygon-click
+
+This sample shows how to make data features respond to mouse events.
+
+## Setup
+
+### Before starting run:
+
+`npm i`
+
+### Run an example on a local web server
+
+`cd samples/dds-datasets-polygon-click`
+`npm start`
+
+### Build an individual example
+
+`cd samples/dds-datasets-polygon-click`
+`npm run build`
+
+From 'samples':
+
+`npm run build --workspace=dds-datasets-polygon-click/`
+
+### Build all of the examples.
+
+From 'samples':
+
+`npm run build-all`
+
+### Run lint to check for problems
+
+`cd samples/dds-datasets-polygon-click`
+`npx eslint index.ts` 
+
+## Feedback
+
+For feedback related to this sample, please open a new issue on
+[GitHub](https://github.com/googlemaps-samples/js-api-samples/issues).
diff --git a/samples/dds-datasets-polygon-click/index.html b/samples/dds-datasets-polygon-click/index.html
@@ -0,0 +1,30 @@
+<!doctype html>
+<!--
+ @license
+ Copyright 2026 Google LLC. All Rights Reserved.
+ SPDX-License-Identifier: Apache-2.0
+-->
+<!-- [START maps_dds_datasets_polygon_click] -->
+<html>
+    <head>
+        <title>Style a polygon data feature</title>
+
+        <link rel="stylesheet" type="text/css" href="./style.css" />
+        <script type="module" src="./index.js"></script>
+        <!-- prettier-ignore -->
+        <script>(g=>{var h,a,k,p="The Google Maps JavaScript API",c="google",l="importLibrary",q="__ib__",m=document,b=window;b=b[c]||(b[c]={});var d=b.maps||(b.maps={}),r=new Set,e=new URLSearchParams,u=()=>h||(h=new Promise(async(f,n)=>{await (a=m.createElement("script"));e.set("libraries",[...r]+"");for(k in g)e.set(k.replace(/[A-Z]/g,t=>"_"+t[0].toLowerCase()),g[k]);e.set("callback",c+".maps."+q);a.src=`https://maps.${c}apis.com/maps/api/js?`+e;d[q]=f;a.onerror=()=>h=n(Error(p+" could not load."));a.nonce=m.querySelector("script[nonce]")?.nonce||"";m.head.append(a)}));d[l]?console.warn(p+" only loads once. Ignoring:",g):d[l]=(f,...n)=>r.add(f)&&u().then(()=>d[l](f,...n))})
+        ({key: "AIzaSyA6myHzS10YXdcazAFalmXvDkrYCp5cLc8", v: "weekly"});</script>
+    </head>
+    <body>
+        <gmp-map
+            center="40.780101, -73.967780"
+            zoom="13"
+            map-id="5cd2c9ca1cf05670"
+            map-type-control="false">
+            <div id="attribution" slot="control-block-end-inline-start">
+                Data source: NYC Open Data
+            </div>
+        </gmp-map>
+    </body>
+</html>
+<!-- [END maps_dds_datasets_polygon_click] -->
diff --git a/samples/dds-datasets-polygon-click/index.ts b/samples/dds-datasets-polygon-click/index.ts
@@ -0,0 +1,109 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+// [START maps_dds_datasets_polygon_click]
+const mapElement = document.querySelector('gmp-map') as google.maps.MapElement;
+let innerMap;
+let lastInteractedFeatureIds: string[] = [];
+let lastClickedFeatureIds: string[] = [];
+let datasetLayer;
+
+// [START maps_dds_datasets_polygon_click_eventhandler]
+// Note, 'globalid' is an attribute in this Dataset.
+function handleClick(/* MouseEvent */ e) {
+    if (e.features) {
+        lastClickedFeatureIds = e.features.map(
+            (f) => f.datasetAttributes['globalid']
+        );
+    }
+    datasetLayer.style = applyStyle;
+}
+
+function handleMouseMove(/* MouseEvent */ e) {
+    if (e.features) {
+        lastInteractedFeatureIds = e.features.map(
+            (f) => f.datasetAttributes['globalid']
+        );
+    }
+    datasetLayer.style = applyStyle;
+}
+// [END maps_dds_datasets_polygon_click_eventhandler]
+
+async function initMap() {
+    // Request needed libraries.
+    (await google.maps.importLibrary('maps')) as google.maps.MapsLibrary;
+
+    // Get the inner map.
+    innerMap = mapElement.innerMap;
+
+    // Dataset ID for NYC park data.
+    const datasetId = 'a75dd002-ad20-4fe6-af60-27cd2ed636b4';
+
+    // [START maps_dds_datasets_polygon_click_addlistener]
+    datasetLayer = innerMap.getDatasetFeatureLayer(datasetId);
+    datasetLayer.style = applyStyle;
+
+    datasetLayer.addListener('click', handleClick);
+    datasetLayer.addListener('mousemove', handleMouseMove);
+
+    // Map event listener.
+    innerMap.addListener('mousemove', () => {
+        // If the map gets a mousemove, that means there are no feature layers
+        // with listeners registered under the mouse, so we clear the last
+        // interacted feature ids.
+        if (lastInteractedFeatureIds?.length) {
+            lastInteractedFeatureIds = [];
+            datasetLayer.style = applyStyle;
+        }
+    });
+    // [END maps_dds_datasets_polygon_click_addlistener]
+}
+
+// [START maps_dds_datasets_polygon_click_stylefunction]
+const styleDefault = {
+    strokeColor: 'green',
+    strokeWeight: 2.0,
+    strokeOpacity: 1.0,
+    fillColor: 'green',
+    fillOpacity: 0.3,
+};
+
+const styleClicked = {
+    ...styleDefault,
+    strokeColor: 'blue',
+    fillColor: 'blue',
+    fillOpacity: 0.5,
+};
+
+const styleMouseMove = {
+    ...styleDefault,
+    strokeWeight: 4.0,
+};
+
+function applyStyle(/* FeatureStyleFunctionOptions */ params) {
+    const datasetFeature = params.feature;
+
+    // Note, 'globalid' is an attribute in this dataset.
+    if (
+        lastClickedFeatureIds.includes(
+            datasetFeature.datasetAttributes['globalid']
+        )
+    ) {
+        return styleClicked;
+    }
+
+    if (
+        lastInteractedFeatureIds.includes(
+            datasetFeature.datasetAttributes['globalid']
+        )
+    ) {
+        return styleMouseMove;
+    }
+    return styleDefault;
+}
+// [END maps_dds_datasets_polygon_click_stylefunction]
+
+initMap();
+// [END maps_dds_datasets_polygon_click]
diff --git a/samples/dds-datasets-polygon-click/package.json b/samples/dds-datasets-polygon-click/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "@js-api-samples/dds-datasets-polygon-click",
+  "version": "1.0.0",
+  "scripts": {
+    "build": "tsc && bash ../jsfiddle.sh dds-datasets-polygon-click && bash ../app.sh dds-datasets-polygon-click && bash ../docs.sh dds-datasets-polygon-click && npm run build:vite --workspace=. && bash ../dist.sh dds-datasets-polygon-click",
+    "test": "tsc && npm run build:vite --workspace=.",
+    "start": "tsc && vite build --base './' && vite",
+    "build:vite": "vite build --base './'",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+
+  }
+}
diff --git a/samples/dds-datasets-polygon-click/style.css b/samples/dds-datasets-polygon-click/style.css
@@ -0,0 +1,24 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+/* [START maps_dds_datasets_polygon_click] */
+/* 
+ * Optional: Makes the sample page fill the window. 
+ */
+html,
+body {
+    height: 100%;
+    margin: 0;
+    padding: 0;
+}
+
+#attribution {
+    background-color: rgba(255, 255, 255, 0.7);
+    font-family: 'Roboto', 'Arial', 'sans-serif';
+    font-size: 10px;
+    padding: 2px;
+    margin: 2px;
+}
+/* [END maps_dds_datasets_polygon_click] */
diff --git a/samples/dds-datasets-polygon-click/tsconfig.json b/samples/dds-datasets-polygon-click/tsconfig.json
@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "module": "esnext",
+    "target": "esnext",
+    "strict": true,
+    "noImplicitAny": false,
+    "lib": [
+      "es2015",
+      "esnext",
+      "es6",
+      "dom",
+      "dom.iterable"
+    ],
+    "moduleResolution": "Node",
+    "jsx": "preserve"
+  }
+}