JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet-0.7.2/leaflet.css">
<script src="http://cdn.leafletjs.com/leaflet-0.7.2/leaflet.js"></script>
<div id="map"></div>

CSS

html, body, #map {
      height: 100%;
      width:100%;
      padding:0px;
      margin:0px;
      font-family: "Helvetica Neue",Helvetica,Arial,sans-serif;
      color: #333;
   }

JavaScript

//////////////////////////////////////////////////////////////////////////////////////////////
//setting up the map//
//////////////////////////////////////////////////////////////////////////////////////////////

// set center coordinates
var centerlat = 34.05;
var centerlon = -118.25;

// set default zoom level
var zoomLevel = 11; 

// initialize map
var map = L.map('map').setView([centerlat,centerlon], zoomLevel);
 
// set source for map tiles (in this case one of Mapbox's minimal example maps)
MB_ATTR = 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
'<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, ' +
'Imagery © <a href="http://mapbox.com">Mapbox</a>';

MB_URL = 'http://{s}.tiles.mapbox.com/v3/{id}/{z}/{x}/{y}.png';

// add tiles to map
L.tileLayer(MB_URL, {attribution: MB_ATTR, id: 'examples.map-szwdot65'}).addTo(map);

//////////////////////////////////////////////////////////////////////////////////////////////
//creating some synthetic GeoJSON data//
//////////////////////////////////////////////////////////////////////////////////////////////

//initialize
var dotlayer;
var dots;
var dotcount = 500;

//cheapo normrand function
function normish(mean, range) {
    var num_out = ((Math.random() + Math.random() + Math.random() + Math.random() - 2) / 2) * range + mean;
    return num_out;
}

//create geojson data with random ~normal distribution
function make_dots() {

    dots = {
        type: "FeatureCollection",
        features: []
    };

     

        //set up random variables
        x = normish(0, 2);
        y = normish(0, 2);
        
        //create points randomly distributed about center coordinates
        var g = { 
            "type": "Point",
            "coordinates":[-5 , 34.796931]
        };
        
        //create feature properties, with year roughly proportional to distance from center coordinates
        var p = {
            "id" : 1,
            "popup":...