JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.7/leaflet.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.7/leaflet.js"></script>
<script src="https://code.jquery.com/jquery-1.12.1.min.js"></script>
<script src="https://code.jquery.com/ui/1.11.3/jquery-ui.min.js"></script>
<script src="https://rawgit.com/dwilhelm89/LeafletSlider/master/SliderControl.js"></script>
<link rel="stylesheet" href="https://code.jquery.com/ui/1.11.3/themes/smoothness/jquery-ui.css">
<div id='map'></div>

CSS

body {
    padding: 0;
    margin: 0;
}

html,
body,
#map {
    height: 100%;
    width: 100%;
}

JavaScript

var sliderControl = null;

var camps = {
    "type": "FeatureCollection",
    "features": [{
        "type": "Feature",
        "properties": {
            "STATUS": "UNOCCUPIED",
            "DATE_START": "2015-06-23",
            "DATE_CLOSED": "2016-01-23"
        },
        "geometry": {
            "type": "Point",
            "coordinates": [64.6875, 34.97600151317591]
        }
    }, {
        "type": "Feature",
        "properties": {
            "STATUS": "OCCUPIED",
            "DATE_START": "2014-01-21",
            "DATE_CLOSED": "2015-05-25"
        },
        "geometry": {
            "type": "Point",
            "coordinates": [65.335693359375, 36.26199220445664]
        }
    }, {
        "type": "Feature",
        "properties": {
            "STATUS": "UNOCCUPIED",
            "DATE_START": "2015-09-13",
            "DATE_CLOSED": ""
        },
        "geometry": {
            "type": "Point",
            "coordinates": [67.587890625, 35.969115075774845]
        }
    }]
};

/*camps.features.sort(function(a, b) {
    return (a.properties.DATE_START > b.properties.DATE_START);
});*/

var map = L.map('map', {
    center: [33.67406853374198, 66.9287109375],
    zoom: 7
}).addLayer(new L.TileLayer("http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"));


//Create a marker layer (in the example done via a GeoJSON FeatureCollection)
var testlayer = L.geoJson(camps, {
    onEachFeature: function(feature, layer) {
        layer.bindPopup(feature.properties.DATE_START);
    }
});

var sliderControl = L.control.sliderControl({
    position: "topright",
    layer: testlayer,
    timeAttribute: 'DATE_START'
});

//Make sure to add the slider to the map ;-)
map.addControl(sliderControl);

sliderControl.options.markers.sort(function(a, b) {
    return (a.feature.properties.DATE_START > b.feature.properties.DATE_START);
});

//And initialize the...