JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://maps.googleapis.com/maps/api/js?v=3.exp&amp;sensor=false"></script>
<body onload="initialize()">
    <div id="map-canvas"></div>
    <div id="locationInput">
        <input id="address" type="textbox" value="Sydney, NSW">
        <input type="button" value="Encode" onclick="codeAddress()">
    </div>
</body>

CSS

#map-canvas {
    width:70%;
    height:480px;
    margin:0 auto;
}
#locationInput {
    width:50%;
    text-align:center;
    margin:0 auto;
}

JavaScript

var geocoder;
var map;
var address;
var infowindow;
var marker;
var currentAddress;

function initialize() {
    geocoder = new google.maps.Geocoder();
    var latlng = new google.maps.LatLng(-34.397, 150.644);
    var mapOptions = {
        zoom: 8,
        center: latlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    }
    map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions);
    addMarker('campbelltown, NSW');
    addMarker('sydney, NSW', 'siteLocation');
    addMarker('oak flats, NSW');
}

function getCurrentAddress(marker) {
    currentAddress = "Address: ";
    geocoder.geocode({
        'latLng': marker.getPosition()
    }, function (results, status) {
        console.log(results[1]);
        if (status == google.maps.GeocoderStatus.OK) {
            if (results[1]) currentAddress += results[1].formatted_address;
            console.log(currentAddress);
        } else {
            currentAddress = "Geocoder failed due to: " + status;
        }
        return currentAddress;
    });

    //return 'Address is: ' + marker.getPosition().lat().toFixed(6) + ' , ' + marker.getPosition().lng().toFixed(6);
}

function addMarker(address, markerType) {
    geocoder.geocode({
        'address': address
    }, function (results, status) {
        if (status == google.maps.GeocoderStatus.OK) {
            map.setCenter(results[0].geometry.location);
            if (markerType == 'siteLocation') {
                marker = new google.maps.Marker({
                    map: map,
                    position: results[0].geometry.location,
                    icon: "http://www.google.com/intl/en_us/mapfiles/ms/micons/blue-dot.png",
                    draggable: true,
                    clickable: true
                });
            } else {
                marker = new google.maps.Marker({
                    map: map,
                    position: results[0].geometry.location,
                    draggable: true,
                   ...