JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://leaflet-cdn.s3.amazonaws.com/build/master/leaflet-src.js"></script>
<link rel="stylesheet" href="http://leaflet-cdn.s3.amazonaws.com/build/master/leaflet.css">
<script src="http://rawgithub.com/kartena/Proj4Leaflet/master/lib/proj4-compressed.js"></script>

<div id="map"></div>

CSS

#map { height: 360px; }

JavaScript

var bp1 = L.point(17736.0314, 23697.0977);
var bp2 = L.point(297289.9391, 245375.4223);
var centerp = L.point(156118.57 132693.79);
var crs31370 = new L.Proj.CRS.TMS(
    "EPSG:31370",
    "+proj=lcc +lat_1=51.16666723333333 +lat_2=49.8333339 +lat_0=90 +lon_0=4.367486666666666 +x_0=150000.013 +y_0=5400088.438 +ellps=intl +towgs84=-106.868628,52.297783,-103.723893,0.336570,-0.456955,1.842183,-1.2747 +units=m +no_defs",
    {bounds: L.bounds(bp1, bp2)}
);


var map = L.map('map', {
        crs: crs31370
    }).setView([51.505, -0.09], 10);

var grb = L.tileLayer.wms("http://10.1.1.17:8080/geoserver/grb/wms", {
    layers: 'grb:Adp',
    format: 'image/png',
    transparent: true,
    version: '1.1.0'
}).addTo(map);

map.locate({setView:true})