letinnerMap;letfeatureLayer;letinfoWindow;letlastInteractedFeatureIds=[];letlastClickedFeatureIds=[];functionhandleClick(/* MouseEvent */e){lastClickedFeatureIds=e.features.map((f)=>f.placeId);lastInteractedFeatureIds=[];featureLayer.style=applyStyle;createInfoWindow(e);}functionhandleMouseMove(/* MouseEvent */e){lastInteractedFeatureIds=e.features.map((f)=>f.placeId);featureLayer.style=applyStyle;}asyncfunctioninitMap(){// Request needed libraries.const{Map,InfoWindow}=(awaitgoogle.maps.importLibrary('maps'))asgoogle.maps.MapsLibrary;// Get the gmp-map element.constmapElement=document.querySelector('gmp-map')asgoogle.maps.MapElement;// Get the inner map.innerMap=mapElement.innerMap;// Set map options.innerMap.setOptions({mapTypeControl:false,});// 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;}});// Create the infowindow.infoWindow=newInfoWindow({});// Apply style on load, to enable clicking.featureLayer.style=applyStyle;}// Helper function for the infowindow.asyncfunctioncreateInfoWindow(event){letfeature=event.features[0];if(!feature.placeId)return;// Update the info window.// Get the place instance from the selected feature.constplace=awaitfeature.fetchPlace();// Create a new div to hold the text content.letcontent=document.createElement('div');// Get the text values.letnameText=document.createElement('span');nameText.textContent=`Display name:${place.displayName}`;letplaceIdText=document.createElement('span');placeIdText.textContent=`Place ID:${feature.placeId}`;letfeatureTypeText=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);}// Define styles.// Stroke and fill with minimum opacity value.conststyleDefault={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.conststyleClicked={...styleDefault,fillColor:'#810FCB',fillOpacity:0.5,};// Style for polygon on mouse move.conststyleMouseMove={...styleDefault,strokeWeight:4.0,};// Apply styles using a feature style function.functionapplyStyle(/* FeatureStyleFunctionOptions */params){constplaceId=params.feature.placeId;//@ts-ignoreif(lastClickedFeatureIds.includes(placeId)){returnstyleClicked;}//@ts-ignoreif(lastInteractedFeatureIds.includes(placeId)){returnstyleMouseMove;}returnstyleDefault;}// Helper function to create an info window.functionupdateInfoWindow(content,center){infoWindow.setContent(content);infoWindow.setPosition(center);infoWindow.open({map:innerMap,shouldFocus:false,});}initMap();
index.ts

letinnerMap;letfeatureLayer;letinfoWindow;letlastInteractedFeatureIds=[];letlastClickedFeatureIds=[];functionhandleClick(/* MouseEvent */e){lastClickedFeatureIds=e.features.map((f)=>f.placeId);lastInteractedFeatureIds=[];featureLayer.style=applyStyle;createInfoWindow(e);}functionhandleMouseMove(/* MouseEvent */e){lastInteractedFeatureIds=e.features.map((f)=>f.placeId);featureLayer.style=applyStyle;}asyncfunctioninitMap(){// Request needed libraries.const{Map,InfoWindow}=(awaitgoogle.maps.importLibrary('maps'));// Get the gmp-map element.constmapElement=document.querySelector('gmp-map');// Get the inner map.innerMap=mapElement.innerMap;// Set map options.innerMap.setOptions({mapTypeControl:false,});// 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;}});// Create the infowindow.infoWindow=newInfoWindow({});// Apply style on load, to enable clicking.featureLayer.style=applyStyle;}// Helper function for the infowindow.asyncfunctioncreateInfoWindow(event){letfeature=event.features[0];if(!feature.placeId)return;// Update the info window.// Get the place instance from the selected feature.constplace=awaitfeature.fetchPlace();// Create a new div to hold the text content.letcontent=document.createElement('div');// Get the text values.letnameText=document.createElement('span');nameText.textContent=`Display name:${place.displayName}`;letplaceIdText=document.createElement('span');placeIdText.textContent=`Place ID:${feature.placeId}`;letfeatureTypeText=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);}// Define styles.// Stroke and fill with minimum opacity value.conststyleDefault={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.conststyleClicked={...styleDefault,fillColor:'#810FCB',fillOpacity:0.5,};// Style for polygon on mouse move.conststyleMouseMove={...styleDefault,strokeWeight:4.0,};// Apply styles using a feature style function.functionapplyStyle(/* FeatureStyleFunctionOptions */params){constplaceId=params.feature.placeId;//@ts-ignoreif(lastClickedFeatureIds.includes(placeId)){returnstyleClicked;}//@ts-ignoreif(lastInteractedFeatureIds.includes(placeId)){returnstyleMouseMove;}returnstyleDefault;}// Helper function to create an info window.functionupdateInfoWindow(content,center){infoWindow.setContent(content);infoWindow.setPosition(center);infoWindow.open({map:innerMap,shouldFocus:false,});}initMap();
index.js

<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: "AIzaSyA6myHzS10YXdcazAFalmXvDkrYCp5cLc8", v: "weekly"});</script>    </head>    <body>        <gmp-map            center="39.23,-105.73"            zoom="8"            map-id="8b37d7206ccf0121a2634fd5"></gmp-map>    </body></html>
index.html