JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://unpkg.com/leaflet@0.7.7/dist/leaflet.css">
<script src="https://unpkg.com/leaflet@0.7.7/dist/leaflet-src.js"></script>
<link rel="stylesheet" href="https://cdn.rawgit.com/Leaflet/Leaflet.draw/v0.3.0/dist/leaflet.draw.css">
<script src="https://cdn.rawgit.com/Leaflet/Leaflet.draw/v0.3.0/dist/leaflet.draw-src.js"></script>
<div id="map"></div>

<button id="convert">
Get all features to GeoJSON string
</button>

CSS

#map {
    height: 500px;
}

JavaScript

var osmUrl = 'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
    osmAttrib = '&copy; <a href="http://openstreetmap.org/copyright">OpenStreetMap</a> contributors',
    osm = L.tileLayer(osmUrl, {
        maxZoom: 18,
        attribution: osmAttrib
    });

map = L.map('map', {
    layers: [osm],
    center: [31.9500, 35.9333],
    zoom: 15
});
var drawnItems = L.geoJson().addTo(map);
map.addControl(new L.Control.Draw({
    edit: {
        featureGroup: drawnItems
    }
}));

map.on('draw:created', function (event) {
    var layer = event.layer,
    	feature = layer.feature = layer.feature || {};
    
    feature.type = feature.type || "Feature";
    var props = feature.properties = feature.properties || {};
    //layer.feature = {properties: {}}; // No need to convert to GeoJSON.
    //var props = layer.feature.properties;
    props.desc = null;
    props.image = null;
    drawnItems.addLayer(layer);
    addPopup(layer);
});

function addPopup(layer) {
	var content = document.createElement("textarea");
    content.addEventListener("keyup", function () {
    	layer.feature.properties.desc = content.value;
    });
    layer.on("popupopen", function () {
    	content.value = layer.feature.properties.desc;
      content.focus();
    });
    layer.bindPopup(content).openPopup();
}

document.getElementById("convert").addEventListener("click", function () {
	console.log(JSON.stringify(drawnItems.toGeoJSON(), null, 2));
});