googlemaps-samples · willum070 · Oct 28, 2025
diff --git a/samples/boundaries-click/README.md b/samples/boundaries-click/README.md
@@ -0,0 +1,40 @@
+# Google Maps JavaScript Sample
+
+This sample is generated from @googlemaps/js-samples located at
+https://github.com/googlemaps-samples/js-api-samples.
+
+## Setup
+
+### Before starting run:
+
+`npm i`
+
+### Run an example on a local web server
+
+`cd samples/boundaries-click`
+`npm start`
+
+### Build an individual example
+
+`cd samples/boundaries-click`
+`npm run build`
+
+From 'samples':
+
+`npm run build --workspace=boundaries-click/`
+
+### Build all of the examples.
+
+From 'samples':
+
+`npm run build-all`
+
+### Run lint to check for problems
+
+`cd samples/boundaries-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/boundaries-click/index.html b/samples/boundaries-click/index.html
@@ -0,0 +1,22 @@
+<!doctype html>
+<!--
+ @license
+ Copyright 2025 Google LLC. All Rights Reserved.
+ SPDX-License-Identifier: Apache-2.0
+-->
+<!-- [START maps_boundaries_click_event] -->
+<html>
+  <head>
+    <title>Handle Region Boundary Click Event</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: "AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg", v: "weekly"});</script>
+  </head>
+  <body>
+    <gmp-map center="39.23,-105.73" zoom="8" map-id="8b37d7206ccf0121a2634fd5">
+  </body>
+</html>
+<!-- [END maps_boundaries_click_event] -->
diff --git a/samples/boundaries-click/index.ts b/samples/boundaries-click/index.ts
@@ -0,0 +1,153 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+// [START maps_boundaries_click_event]
+let innerMap;
+let featureLayer;
+let infoWindow;
+let lastInteractedFeatureIds = [];
+let lastClickedFeatureIds = [];
+
+// [START maps_boundaries_click_event_handler]
+function handleClick(/* MouseEvent */ e) {
+    lastClickedFeatureIds = e.features.map((f) => f.placeId);
+    lastInteractedFeatureIds = [];
+    featureLayer.style = applyStyle;
+    createInfoWindow(e);
+}
+
+function handleMouseMove(/* MouseEvent */ e) {
+    lastInteractedFeatureIds = e.features.map((f) => f.placeId);
+    featureLayer.style = applyStyle;
+}
+// [END maps_boundaries_click_event_handler]
+
+async function initMap() {
+    // Request needed libraries.
+    const { Map, InfoWindow } = (await google.maps.importLibrary(
+        'maps'
+    )) as google.maps.MapsLibrary;
+
+    // Get the gmp-map element.
+    const mapElement = document.querySelector(
+        'gmp-map'
+    ) as google.maps.MapElement;
+
+    // Get the inner map.
+    innerMap = mapElement.innerMap;
+
+    // Set map options.
+    innerMap.setOptions({
+        mapTypeControl: false,
+    });
+
+    //[START maps_boundaries_click_event_add_layer]
+    // Add the feature layer.
+    featureLayer = innerMap.getFeatureLayer(
+        google.maps.FeatureType.ADMINISTRATIVE_AREA_LEVEL_2
+    );
+
+    // Add the event listeners for the feature layer.
+    featureLayer.addListener('click', handleClick);
+    featureLayer.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 = [];
+            featureLayer.style = applyStyle;
+        }
+    });
+    //[END maps_boundaries_click_event_add_layer]
+
+    // Create the infowindow.
+    infoWindow = new InfoWindow({});
+    // Apply style on load, to enable clicking.
+    featureLayer.style = applyStyle;
+}
+
+// Helper function for the infowindow.
+async function createInfoWindow(event) {
+    let feature = event.features[0];
+    if (!feature.placeId) return;
+
+    // Update the info window.
+    // Get the place instance from the selected feature.
+    const place = await feature.fetchPlace();
+
+    // Create a new div to hold the text content.
+    let content = document.createElement('div');
+
+    // Get the text values.
+    let nameText = document.createElement('span');
+    nameText.textContent = `Display name: ${place.displayName}`;
+    let placeIdText = document.createElement('span');
+    placeIdText.textContent = `Place ID: ${feature.placeId}`;
+    let featureTypeText = document.createElement('span');
+    featureTypeText.textContent = `Feature type: ${feature.featureType}`;
+
+    // Append the text to the div.
+    content.appendChild(nameText);
+    content.appendChild(document.createElement('br'));
+    content.appendChild(placeIdText);
+    content.appendChild(document.createElement('br'));
+    content.appendChild(featureTypeText);
+
+    updateInfoWindow(content, event.latLng);
+}
+
+// [START maps_boundaries_click_event_style]
+// Define styles.
+// Stroke and fill with minimum opacity value.
+const styleDefault = {
+    strokeColor: '#810FCB',
+    strokeOpacity: 1.0,
+    strokeWeight: 2.0,
+    fillColor: 'white',
+    fillOpacity: 0.1, // Polygons must be visible to receive events.
+};
+// Style for the clicked polygon.
+const styleClicked = {
+    ...styleDefault,
+    fillColor: '#810FCB',
+    fillOpacity: 0.5,
+};
+// Style for polygon on mouse move.
+const styleMouseMove = {
+    ...styleDefault,
+    strokeWeight: 4.0,
+};
+
+// Apply styles using a feature style function.
+function applyStyle(/* FeatureStyleFunctionOptions */ params) {
+    const placeId = params.feature.placeId;
+    //@ts-ignore
+    if (lastClickedFeatureIds.includes(placeId)) {
+        return styleClicked;
+    }
+    //@ts-ignore
+    if (lastInteractedFeatureIds.includes(placeId)) {
+        return styleMouseMove;
+    }
+    return styleDefault;
+}
+// [END maps_boundaries_click_event_style]
+
+// Helper function to create an info window.
+function updateInfoWindow(content, center) {
+    infoWindow.setContent(content);
+    infoWindow.setPosition(center);
+    infoWindow.open({
+        map: innerMap,
+        shouldFocus: false,
+    });
+}
+
+initMap();
+//  [END maps_boundaries_click_event]
diff --git a/samples/boundaries-click/package.json b/samples/boundaries-click/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "@js-api-samples/boundaries-click",
+  "version": "1.0.0",
+  "scripts": {
+    "build": "tsc && bash ../jsfiddle.sh boundaries-click && bash ../app.sh boundaries-click && bash ../docs.sh boundaries-click && npm run build:vite --workspace=. && bash ../dist.sh boundaries-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/boundaries-click/style.css b/samples/boundaries-click/style.css
@@ -0,0 +1,25 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+/* [START maps_boundaries_click_event] */
+/* 
+ * Always set the map height explicitly to define the size of the div element
+ * that contains the map. 
+ */
+gmp-map {
+    height: 100%;
+}
+
+/* 
+ * Optional: Makes the sample page fill the window. 
+ */
+html,
+body {
+    height: 100%;
+    margin: 0;
+    padding: 0;
+}
+
+/* [END maps_boundaries_click_event] */
diff --git a/samples/boundaries-click/tsconfig.json b/samples/boundaries-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"
+  }
+}