JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://maps.googleapis.com/maps/api/js?sensor=false&amp;libraries=geometry,places&amp;ext=.js"></script>
<div id="map_canvas" style="border: 2px solid #3872ac;"></div>

CSS

html, body, #map_canvas {
    height: 100%;
    width: 100%;
    margin: 0px;
    padding: 0px
}

JavaScript

var geocoder;
var map;

function initialize() {
    var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
        center: new google.maps.LatLng(37.4419, -122.1419),
        zoom: 13,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    });
    var US = {
        NorthEast: {
            lat: 49.38,
            lng: -66.94
        },
        SouthWest: {
            lat: 25.82,
            lng: -124.39
        }
    }
    var USbounds = new google.maps.LatLngBounds(new google.maps.LatLng(US.SouthWest.lat, US.SouthWest.lng),
    new google.maps.LatLng(US.NorthEast.lat, US.NorthEast.lng));
    map.fitBounds(USbounds);
    var USrect = new google.maps.Rectangle({map:map, bounds: USbounds});
}
google.maps.event.addDomListener(window, "load", initialize);