JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://openlayers.org/en/v3.0.0/css/ol.css">
<script src="http://openlayers.org/en/v3.0.0/build/ol.js"></script>
 <div id="map" class="map"></div>

CSS

.map {
    height: 100%;
    width: 100%;
}

JavaScript

var map = new ol.Map({
    target: 'map',
    layers: [
        new ol.layer.Tile({
            source: new ol.source.MapQuest({layer: 'sat'})
        })
    ],
    view: new ol.View({
        center: ol.proj.transform([37.41, 8.82], 'EPSG:4326', 'EPSG:3857'),
        zoom: 4
    })
});

map.on("click", function(evt) {
    var coord = ol.proj.transform(evt.coordinate, 'EPSG:3857', 'EPSG:4326');
    var lon = coord[0];
    var lat = coord[1];
    alert(lon);
    alert(lat);
});