routes-get-alternatives

Sample code supporting Google Maps Platform JavaScript API documentation. author(s): Geo Developer IX Documentation Team

HTML

<!doctype html>
<!--
 @license
 Copyright 2025 Google LLC. All Rights Reserved.
 SPDX-License-Identifier: Apache-2.0
-->

<html>
    <head>
        <title>Get directions</title>

        <link rel="stylesheet" type="text/css" href="./style.css" />
        <script type="module" src="./index.js"></script>
        <script>
            // prettier-ignore
            (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: "GOOGLE_MAPS_API_KEY"
            });
        </script>
    </head>
    <body>
        <gmp-map center="37.447646, -122.113878" zoom="10"></gmp-map>
    </body>
</html>

CSS

/*
 * @license
 * Copyright 2025 Google LLC. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */

/*
 * 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;
}

JavaScript

'use strict';
/*
 * @license
 * Copyright 2025 Google LLC. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */

const mapPolylines = [];
const mapElement = document.querySelector('gmp-map');
let innerMap;

// Initialize and add the map.
async function init() {
    //  Request the needed libraries.
    const [{ event }] = await Promise.all([
        google.maps.importLibrary('core'),
        google.maps.importLibrary('maps'),
    ]);

    innerMap = mapElement.innerMap;
    innerMap.setOptions({
        mapTypeControl: false,
        mapId: 'DEMO_MAP_ID',
    });

    // Call the function after the map is loaded.
    event.addListenerOnce(innerMap, 'idle', () => {
        void getDirections();
    });
}

async function getDirections() {
    // Request the needed libraries.
    const [{ Route, RouteLabel }] = await Promise.all([
        google.maps.importLibrary('routes'),
    ]);

    // Build a request.
    const request = {
        origin: 'San Francisco, CA',
        destination: 'Sunset Dr Pacific Grove, CA 93950',
        travelMode: 'DRIVING',
        computeAlternativeRoutes: true,
        fields: ['path', 'routeLabels', 'viewport'], // Request the routeLabels field.
    };

    // Call computeRoutes to get the directions.
    const result = await Route.computeRoutes(request);
    if (!result.routes || result.routes.length === 0) {
        console.warn('No routes found');
        return;
    }

    let primaryRoute;

    for (const route of result.routes) {
        // Save the primary route for last so it's drawn on top.
        if (
            // Check for the default route.
            route.routeLabels?.includes(RouteLabel.DEFAULT_ROUTE)
        ) {
            primaryRoute = route;
        } else {
            drawRoute(route, false);
        }
    }

    if (primaryRoute) {
        drawRoute(primaryRoute, true);
        await primaryRoute.createWaypointAdvancedMarkers({ map: innerMap });
        innerMap.fitBounds(primaryRoute.viewport,...