JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.css">
<script src="https://api.tiles.mapbox.com/mapbox.js/plugins/leaflet-heat/v0.1.3/leaflet-heat.js"></script>
<div id="map"></div>

CSS

#map {
    width:1000px;
    height:1000px;
}

JavaScript

var addressPoints = [
[-37.8210922667, 175.2209316333, "2"],
];

var map = L.map('map').setView([0, 0], 2);

var heat = L.heatLayer(addressPoints, {
    maxZoom: 18
}).addTo(map);
var draw = true;


var land = L.tileLayer.wms("http://demo.opengeo.org/geoserver/wms", {
    layers: 'maps:ne_50m_land',
    format: 'image/png',
    transparent: true,
    attribution: "© OpenGeo"
}).addTo(map);

document.getElementsByClassName('leaflet-tile-pane')[0].style.zIndex = 10;