JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://maps.googleapis.com/maps/api/js?sensor=false&amp;extension=.js"></script>
<div id="map"></div>

CSS

#map {
     height: 500px;
     width: 500px;
 }

JavaScript

var map;
var markers = {};
// add marker to object
var posi = new google.maps.LatLng(53.801279, -1.548567);
var name = 'Vince';
markers[name] = {};
markers[name].id = 1;
markers[name].lat = 53.801279;
markers[name].lng = -1.548567;
markers[name].state = 'Online';
markers[name].position = posi;
markers[name].selected = false;

$(document).ready(function () {

    var mapOptions = {
        zoom: 5,
        center: new google.maps.LatLng(53.801279, -1.548567),
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    map = new google.maps.Map(document.getElementById('map'), mapOptions);
    var infowindow = new google.maps.InfoWindow();
    for (var key in markers) {
        marker = new google.maps.Marker({
            position: new google.maps.LatLng(markers[key].lat, markers[key].lng),
            map: map
        });

        google.maps.event.addListener(marker, 'click', (function (marker, key) {
            return function () {
                infowindow.setContent(key);
                infowindow.open(map, marker);
            }
        })(marker, key));
    }

    // Start drag rectangle to select markers !!!!!!!!!!!!!!!!
    var shiftPressed = false;

    $(window).keydown(function (evt) {
        if (evt.which === 16) { // shift
            shiftPressed = true;
        }
    }).keyup(function (evt) {
        if (evt.which === 16) { // shift
            shiftPressed = false;
        }
    });

    var mouseDownPos, gribBoundingBox = null,
        mouseIsDown = 0;
    var themap = map;

    google.maps.event.addListener(themap, 'mousemove', function (e) {
        if (mouseIsDown && shiftPressed) {
            if (gribBoundingBox !== null) // box exists
            {
                var bounds;

                if ((e.latLng.jb > mouseDownPos.jb ) && (e.latLng.kb > mouseDownPos.kb)) {
                    bounds = new google.maps.LatLngBounds(mouseDownPos, e.latLng);   
                } else if ((e.latLng.jb > mouseDownPos.jb ) && (e.latLng.kb <...