Editor's Note: This article originally appeared on mapbox.com and is being republished with permission from the provider. Readers going through this tutorial are assumed to have some familiarity with front-end development concepts. Some advanced JavaScript required.

This guide will walk you through how to create a store locator map using Mapbox GL JS. You'll be able to browse all of the locations from a sidebar and select a specific store to view more information. Selecting a marker on the map will highlight the selected store on the sidebar.

You will use Sweetgreen, a local salad shop, as an example. They have a healthy number of locations, plus their salads are delicious!

This guide takes a deep dive into JavaScript with Mapbox GL JS to build an interactive web map. If you're new to Mapbox GL JS you might want to check out our guide on Mapbox Web applications first.

Getting started

For this project, we recommend that you create a local folder called "store-locator" to house your project files. You'll see this folder referred to as your project folder.

There are a few resources you'll need before getting started:

Custom map marker. You'll be using an image for your map marker. Save the image to your project folder. ↓ Download custom marker

Add structure

In your project folder, create an index.html file. Set up the document by adding Mapbox GL JS and CSS to your head :

<script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.50.0/mapbox-gl.js'></script> <link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.50.0/mapbox-gl.css' rel='stylesheet' />

Next, markup the page to create a map container and sidebar listing:

<div class='sidebar pad2'>Listing</div> <div id='map' class='map pad2'>Map</div>

Then, apply some CSS to create the page layout:

body { background: #404040; color: #f8f8f8; font: 500 20px/26px 'Helvetica Neue', Helvetica, Arial, Sans-serif; margin: 0; padding: 0; -webkit-font-smoothing: antialiased; } /* The page is split between map and sidebar - the sidebar gets 1/3, map gets 2/3 of the page. You can adjust this to your personal liking. */ .sidebar { width: 33.3333%; } .map { border-left: 1px solid #fff; position: absolute; left: 33.3333%; width: 66.6666%; top: 0; bottom: 0; } .pad2 { padding: 20px; -webkit-box-sizing: border-box; -moz-box-sizing: border-box; box-sizing: border-box; }



View demo one.

Initialize the map

Now that you have the structure of the page, initialize the map with Mapbox GL JS.

First, add your access token using mapboxgl.accessToken . Then, create a new map object using new mapboxgl.Map() and store it in a variable called map :

mapboxgl.accessToken = '<your access token here>'; // This adds the map to your page var map = new mapboxgl.Map({ // container id specified in the HTML container: 'map', // style URL style: 'mapbox://styles/mapbox/light-v9', // initial position in [lon, lat] format center: [-77.034084, 38.909671], // initial zoom zoom: 14 });

As you can see above, the Mapbox GL JS map requires several options:

container : the id of the <div> element on the page where the map should live. In this case, the id for the <div> is 'map' .

: the of the element on the page where the map should live. In this case, the id for the is . style : the style URL for the map style. In this case, use the Mapbox Light map which has the style URL mapbox://styles/mapbox/light-9 .

: the style URL for the map style. In this case, use the Mapbox Light map which has the style URL . center : the initial centerpoint of the map in [longitude, latitude] format.

: the initial centerpoint of the map in [longitude, latitude] format. zoom : the initial zoom level of the map.

Load data

With Mapbox GL JS, map rendering happens in the browser, which makes your map fast. In order for the browser to render your map, you need to add a layer with geospatial data and instructions for how that data should be rendered.

In order to add a source to the map, your code needs to access the geospatial data. Store all of the GeoJSON data in sweetgreen.geojson in a variable called stores :

var stores = { // data from sweetgreen.geojson, downloaded above };

Now you can add a layer that contains this data and describes how it should be rendered. Add the data to your map once the map loads using addLayer() . Create a new layer, and specify stores as a GeoJSON data source. Then, add instructions for rendering the source. This example only adds minimal styling — for full details on all of the layer styling options, see the Mapbox Style Specification:

map.on('load', function(e) { // Add the data to your map as a layer map.addLayer({ id: 'locations', type: 'symbol', // Add a GeoJSON source containing place coordinates and information. source: { type: 'geojson', data: stores }, layout: { 'icon-image': 'restaurant-15', 'icon-allow-overlap': true, } }); });

Note: restaurant-15 refers to an icon in the Mapbox Light style you added earlier in the code.



View demo two.

Build store listing

Now that the points are on your map, it's time to build the restaurant location listing by iterating through the GeoJSON and creating a list of restaurants dynamically. This means that if you need to add a location then you only need to update the GeoJSON.

First, update the sidebar HTML to hold the listing information and update your CSS to accommodate the layout changes:

<div class='sidebar'> <div class='heading'> <h1>Our locations</h1> </div> <div id='listings' class='listings'></div> </div>

body { color: #404040; font: 400 15px/22px 'Source Sans Pro', 'Helvetica Neue', Sans-serif; margin: 0; padding: 0; -webkit-font-smoothing: antialiased; } * { -webkit-box-sizing: border-box; -moz-box-sizing: border-box; box-sizing: border-box; } h1 { font-size: 22px; margin: 0; font-weight: 400; line-height: 20px; padding: 20px 2px; } a { color: #404040; text-decoration: none; } a:hover { color: #101010; } .sidebar { position: absolute; width: 33.3333%; height: 100%; top: 0; left: 0; overflow: hidden; border-right: 1px solid rgba(0, 0, 0, 0.25); } .pad2 { padding: 20px; } .map { position: absolute; left: 33.3333%; width: 66.6666%; top: 0; bottom: 0; } .heading { background: #fff; border-bottom: 1px solid #eee; height: 60px; line-height: 60px; padding: 0 10px; } .listings { height: 100%; overflow: auto; padding-bottom: 60px; } .listings .item { display: block; border-bottom: 1px solid #eee; padding: 10px; text-decoration: none; } .listings .item:last-child { border-bottom: none; } .listings .item .title { display: block; color: #00853e; font-weight: 700; } .listings .item .title small { font-weight: 400; } .listings .item.active .title, .listings .item .title:hover { color: #8cc63f; } .listings .item.active { background-color: #f8f8f8; } ::-webkit-scrollbar { width: 3px; height: 3px; border-left: 0; background: rgba(0, 0, 0, 0.1); } ::-webkit-scrollbar-track { background: none; } ::-webkit-scrollbar-thumb { background: #00853e; border-radius: 0; } .clearfix { display: block; } .clearfix::after { content: '.'; display: block; height: 0; clear: both; visibility: hidden; }

Next, build a function to iterate through the Sweetgreen locations and add each one to the sidebar listing:

function buildLocationList(data) { // Iterate through the list of stores for (i = 0; i < data.features.length; i++) { var currentFeature = data.features[i]; // Shorten data.feature.properties to just 'prop' so we're not // writing this long form over and over again. var prop = currentFeature.properties; // Select the listing container in the HTML and append a div // with the class 'item' for each store var listings = document.getElementById('listings'); var listing = listings.appendChild(document.createElement('div')); listing.className = 'item'; listing.id = 'listing-' + i; // Create a new link with the class 'title' for each store // and fill it with the store address var link = listing.appendChild(document.createElement('a')); link.href = '#'; link.className = 'title'; link.dataPosition = i; link.innerHTML = prop.address; // Create a new div with the class 'details' for each store // and fill it with the city and phone number var details = listing.appendChild(document.createElement('div')); details.innerHTML = prop.city; if (prop.phone) { details.innerHTML += ' · ' + prop.phoneFormatted; } } }

Then, you will need to call this function when the map loads. You can do this by adding buildLocationList(stores); inside your map.on('load', ...) function after addLayer() . The result will look like this:



View demo three.

Make the map interactive

When a user clicks a link in the sidebar or on a point on the map, you want three things to happen:

The map to fly to the associated store location. A popup to be displayed at that point. The listing to be highlighted in the sidebar.

This will require a bit more code, but you can do it!

Define interactivity functions

First, define two functions: one that flies the map to the correct store, and one that displays a popup at that point. These functions will be fired both when a user clicks on a link in the sidebar listing and when a user clicks on a store location in the map. (Highlighting the listing on the sidebar will be handled separately for the two different click events.)

function flyToStore(currentFeature) { map.flyTo({ center: currentFeature.geometry.coordinates, zoom: 15 }); } function createPopUp(currentFeature) { var popUps = document.getElementsByClassName('mapboxgl-popup'); // Check if there is already a popup on the map and if so, remove it if (popUps[0]) popUps[0].remove(); var popup = new mapboxgl.Popup({ closeOnClick: false }) .setLngLat(currentFeature.geometry.coordinates) .setHTML('<h3>Sweetgreen</h3>' + '<h4>' + currentFeature.properties.address + '</h4>') .addTo(map); }

You can also style your popups using CSS:

/* Marker tweaks */ .mapboxgl-popup-close-button { display: none; } .mapboxgl-popup-content { font: 400 15px/22px 'Source Sans Pro', 'Helvetica Neue', Sans-serif; padding: 0; width: 180px; } .mapboxgl-popup-content-wrapper { padding: 1%; } .mapboxgl-popup-content h3 { background: #91c949; color: #fff; margin: 0; display: block; padding: 10px; border-radius: 3px 3px 0 0; font-weight: 700; margin-top: -15px; } .mapboxgl-popup-content h4 { margin: 0; display: block; padding: 10px; font-weight: 400; } .mapboxgl-popup-content div { padding: 10px; } .mapboxgl-container .leaflet-marker-icon { cursor: pointer; } .mapboxgl-popup-anchor-top > .mapboxgl-popup-content { margin-top: 15px; } .mapboxgl-popup-anchor-top > .mapboxgl-popup-tip { border-bottom-color: #91c949; } In order for the .remove() method to work in older browsers, you will need to include the code below at the beginning of your script: // This will let you use the .remove() function later on if (!('remove' in Element.prototype)) { Element.prototype.remove = function() { if (this.parentNode) { this.parentNode.removeChild(this); } }; }

See the HTML documentation for more information.

Add event listeners

Now that you've defined these two functions, you want them to fire when a user clicks on a restaurant in the sidebar listing or when a user clicks on a restaurant on the map. To do this, you will add event listeners that listen for "click" events and execute some function when they happen. You will add two event listeners: one for when a link in the sidebar is clicked and one for when a location on the map is clicked.

Use this code for when a link is clicked:

// Add an event listener for the links in the sidebar listing link.addEventListener('click', function(e) { // Update the currentFeature to the store associated with the clicked link var clickedListing = data.features[this.dataPosition]; // 1. Fly to the point associated with the clicked link flyToStore(clickedListing); // 2. Close all other popups and display popup for clicked store createPopUp(clickedListing); // 3. Highlight listing in sidebar (and remove highlight for all other listings) var activeItem = document.getElementsByClassName('active'); if (activeItem[0]) { activeItem[0].classList.remove('active'); } this.parentNode.classList.add('active'); });

Use this code for when a location on the map is clicked:

// Add an event listener for when a user clicks on the map map.on('click', function(e) { // Query all the rendered points in the view var features = map.queryRenderedFeatures(e.point, { layers: ['locations'] }); if (features.length) { var clickedPoint = features[0]; // 1. Fly to the point flyToStore(clickedPoint); // 2. Close all other popups and display popup for clicked store createPopUp(clickedPoint); // 3. Highlight listing in sidebar (and remove highlight for all other listings) var activeItem = document.getElementsByClassName('active'); if (activeItem[0]) { activeItem[0].classList.remove('active'); } // Find the index of the store.features that corresponds to the clickedPoint that fired the event listener var selectedFeature = clickedPoint.properties.address; for (var i = 0; i < stores.features.length; i++) { if (stores.features[i].properties.address === selectedFeature) { selectedFeatureIndex = i; } } // Select the correct list item using the found index and add the active class var listing = document.getElementById('listing-' + selectedFeatureIndex); listing.classList.add('active'); } });



View demo four.

Add custom markers

This section will walk you through how to replace the existing standard symbol layer with custom markers. First, you will need to remove the existing symbol layer and related functions. Remove the symbol layer by deleting the .addLayer() function from your code, and replace it with the .addSource() code below. Instead of styling the symbol layer with addLayer , you will use the Markers API to add an image to each point in the GeoJSON data:

map.addSource('places', { type: 'geojson', data: stores });

You'll also want to delete the function that listened for a click on a symbol to fly to the location, display a popup, and highlight the list item. Then, add the custom Sweetgreen icons to the map using mapboxgl.Marker() objects. Unlike the symbol layer, which has symbols embedded in the map, mapboxgl.Marker() objects are HTML DOM elements that can be styled with CSS. Add a new class to the CSS called .marker and set the Sweetgreen marker you downloaded earlier as the background-image :

.marker { border: none; cursor: pointer; height: 56px; width: 56px; background-image: url(marker.png); background-color: rgba(0, 0, 0, 0); }

To add the new markers to the map, iterate through all stores and add the new marker to the map at each location:

stores.features.forEach(function(marker) { // Create a div element for the marker var el = document.createElement('div'); // Add a class called 'marker' to each div el.className = 'marker'; // By default the image for your custom marker will be anchored // by its center. Adjust the position accordingly // Create the custom markers, set their position, and add to map new mapboxgl.Marker(el, { offset: [0, -23] }) .setLngLat(marker.geometry.coordinates) .addTo(map); });

Add new event listeners

Now that you have replaced your symbols with markers, you will need to re-add some code for flying to the position on the map, displaying a popup, and highlighting the list item in the sidebar when clicking on the marker. Within your forEach function from above, add an event listener:

el.addEventListener('click', function(e) { var activeItem = document.getElementsByClassName('active'); // 1. Fly to the point flyToStore(marker); // 2. Close all other popups and display popup for clicked store createPopUp(marker); // 3. Highlight listing in sidebar (and remove highlight for all other listings) e.stopPropagation(); if (activeItem[0]) { activeItem[0].classList.remove('active'); } var listing = document.getElementById('listing-' + i); console.log(listing); listing.classList.add('active'); });

Final tweaks

You will need to adjust the position of the popup to account for the added height of the marker. You can do this using CSS:

.mapboxgl-popup { padding-bottom: 50px; }

At this point, you can also freshen up the type with Source Sans Pro:

<link href='https://fonts.googleapis.com/css?family=Source+Sans+Pro:400,700' rel='stylesheet'>

You'll need to update the font property in body style:

font: 400 15px/22px 'Source Sans Pro', 'Helvetica Neue', Sans-serif;

Finished product

Check out your finished store locator. Great job!



View demo five.

Next steps

After this guide, you should be set with the tools to create your own store locator. Check out more Mapbox GL JS resources on our help page.