Simple Polylines

// This example creates a 2-pixel-wide red polyline showing the path of
// the first trans-Pacific flight between Oakland, CA, and Brisbane,
// Australia which was made by Charles Kingsford Smith.
const mapElement = document.querySelector('gmp-map')!;
let innerMap: google.maps.Map;

async function init() {
    const { Polyline } = await google.maps.importLibrary('maps');
    innerMap = mapElement.innerMap;

    const flightPlanCoordinates = [
        { lat: 37.772, lng: -122.214 },
        { lat: 21.291, lng: -157.821 },
        { lat: -18.142, lng: 178.431 },
        { lat: -27.467, lng: 153.027 },
    ];
    const flightPath = new Polyline({
        path: flightPlanCoordinates,
        geodesic: true,
        strokeColor: '#FF0000',
        strokeOpacity: 1.0,
        strokeWeight: 2,
    });

    flightPath.setMap(innerMap);
}

void init();
index.ts

// This example creates a 2-pixel-wide red polyline showing the path of
// the first trans-Pacific flight between Oakland, CA, and Brisbane,
// Australia which was made by Charles Kingsford Smith.
const mapElement = document.querySelector('gmp-map');
let innerMap;

async function init() {
    const { Polyline } = await google.maps.importLibrary('maps');
    innerMap = mapElement.innerMap;

    const flightPlanCoordinates = [
        { lat: 37.772, lng: -122.214 },
        { lat: 21.291, lng: -157.821 },
        { lat: -18.142, lng: 178.431 },
        { lat: -27.467, lng: 153.027 },
    ];
    const flightPath = new Polyline({
        path: flightPlanCoordinates,
        geodesic: true,
        strokeColor: '#FF0000',
        strokeOpacity: 1.0,
        strokeWeight: 2,
    });

    flightPath.setMap(innerMap);
}

void init();
index.js

/* 
 * Optional: Makes the sample page fill the window. 
 */
html,
body {
    height: 100%;
    margin: 0;
    padding: 0;
}
style.css

<html>
    <head>
        <title>Simple Polylines</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="0, -180" zoom="3" map-type-id="terrain"> </gmp-map>
    </body>
</html>
index.html