JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js?sensor=false"></script>
<h1 class="">Lazy Load Google Map</h1> 
<a href="#myMapModal" class="btn" data-toggle="modal">Launch Map Modal</a>

<div class="modal fade" id="myMapModal">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
                 <h4 class="modal-title">Modal title</h4>

            </div>
            <div class="modal-body">
                <div class="container">
                    <div class="row">
                        <div id="map-canvas" class=""></div>
                    </div>
                </div>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                <button type="button" class="btn btn-primary">Save changes</button>
            </div>
        </div>
        <!-- /.modal-content -->
    </div>
    <!-- /.modal-dialog -->
    </div>
    <!-- /.modal -->

CSS

html, body, #map-canvas  {
  margin: 0;
  padding: 0;
  height: 100%;
}

#map-canvas {
  width:500px;
  height:480px;
}

JavaScript

var map;        
var myCenter=new google.maps.LatLng(53, -1.33);
var marker=new google.maps.Marker({
    position:myCenter
});

function initialize() {
  var mapProp = {
      center:myCenter,
      zoom: 14,
      draggable: false,
      scrollwheel: false,
      mapTypeId:google.maps.MapTypeId.ROADMAP
  };
  
  map=new google.maps.Map(document.getElementById("map-canvas"),mapProp);
  marker.setMap(map);
    
  google.maps.event.addListener(marker, 'click', function() {
      
    infowindow.setContent(contentString);
    infowindow.open(map, marker);
    
  }); 
};
google.maps.event.addDomListener(window, 'load', initialize);

google.maps.event.addDomListener(window, "resize", resizingMap());

$('#myMapModal').on('show.bs.modal', function() {
   //Must wait until the render of the modal appear, thats why we use the resizeMap and NOT resizingMap!! ;-)
   resizeMap();
})

function resizeMap() {
   if(typeof map =="undefined") return;
   setTimeout( function(){resizingMap();} , 400);
}

function resizingMap() {
   if(typeof map =="undefined") return;
   var center = map.getCenter();
   google.maps.event.trigger(map, "resize");
   map.setCenter(center); 
}