Introducing Places UI Kit: A ready-to-use, low-cost component library that lets you bring the familiar Google Maps UI for Places to any map of your choice. Try it out, andshare your input to help shape the future of GMP!
Data Layer: Dynamic Styling
This example uses a data layer to dynamically change the appearance of someKMLfeature objectswhen the user hovers over or clicks them.
Read thedocumentation.
TypeScript
letmap:google.maps.Map;functioninitMap():void{map=newgoogle.maps.Map(document.getElementById("map")asHTMLElement,{zoom:4,center:{lat:-28,lng:137},});// Load GeoJSON.map.data.loadGeoJson("https://storage.googleapis.com/mapsdevsite/json/google.json");// Color each letter gray. Change the color when the isColorful property// is set to true.map.data.setStyle((feature)=>{letcolor="gray";if(feature.getProperty("isColorful")){color=feature.getProperty("color")asstring;}return/** @type {!google.maps.Data.StyleOptions} */{fillColor:color,strokeColor:color,strokeWeight:2,};});// When the user clicks, set 'isColorful', changing the color of the letters.map.data.addListener("click",(event)=>{event.feature.setProperty("isColorful",true);});// When the user hovers, tempt them to click by outlining the letters.// Call revertStyle() to remove all overrides. This will use the style rules// defined in the function passed to setStyle()map.data.addListener("mouseover",(event)=>{map.data.revertStyle();map.data.overrideStyle(event.feature,{strokeWeight:8});});map.data.addListener("mouseout",(event)=>{map.data.revertStyle();});}declareglobal{interfaceWindow{initMap:()=>void;}}window.initMap=initMap;
JavaScript
letmap;functioninitMap(){map=newgoogle.maps.Map(document.getElementById("map"),{zoom:4,center:{lat:-28,lng:137},});// Load GeoJSON.map.data.loadGeoJson("https://storage.googleapis.com/mapsdevsite/json/google.json",);// Color each letter gray. Change the color when the isColorful property// is set to true.map.data.setStyle((feature)=>{letcolor="gray";if(feature.getProperty("isColorful")){color=feature.getProperty("color");}return/** @type {!google.maps.Data.StyleOptions} */{fillColor:color,strokeColor:color,strokeWeight:2,};});// When the user clicks, set 'isColorful', changing the color of the letters.map.data.addListener("click",(event)=>{event.feature.setProperty("isColorful",true);});// When the user hovers, tempt them to click by outlining the letters.// Call revertStyle() to remove all overrides. This will use the style rules// defined in the function passed to setStyle()map.data.addListener("mouseover",(event)=>{map.data.revertStyle();map.data.overrideStyle(event.feature,{strokeWeight:8});});map.data.addListener("mouseout",(event)=>{map.data.revertStyle();});}window.initMap=initMap;
CSS
/* * Always set the map height explicitly to define the size of the div element * that contains the map. */#map{height:100%;}/* * Optional: Makes the sample page fill the window. */html,body{height:100%;margin:0;padding:0;}
HTML
<html> <head> <title>Data Layer: Dynamic Styling</title> <link rel="stylesheet" type="text/css" href="./style.css" /> <script type="module" src="./index.js"></script> </head> <body> <div></div> <!-- The `defer` attribute causes the script to execute after the full HTML document has been parsed. For non-blocking uses, avoiding race conditions, and consistent behavior across browsers, consider loading using Promises. See https://developers.google.com/maps/documentation/javascript/load-maps-js-api for more information. --> <script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly" defer ></script> </body></html>
Try Sample
Clone Sample
Git and Node.js are required to run this sample locally. Follow theseinstructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.
gitclone-bsample-layer-data-dynamichttps://github.com/googlemaps/js-samples.gitcdjs-samplesnpminpmstart
Other samples can be tried by switching to any branch beginning withsample-SAMPLE_NAME.
gitcheckoutsample-SAMPLE_NAMEnpminpmstart
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Last updated 2025-07-18 UTC.