fitBounds. Enable Leaflet. Keep #map { height: 320px } in CSS.

Goal

Run every block and confirm the chart is visible.

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

#map { height: 320px; width: 100%; }

const map = L.map("map").setView([-1.29, 36.82], 6);
L.tileLayer("https://tile.openstreetmap.org/{z}/{x}/{y}.png", { attribution: "© OSM" }).addTo(map);
const a = L.marker([-1.29,36.82]).addTo(map);
const b = L.marker([-4.04,39.67]).addTo(map);
map.fitBounds(L.featureGroup([a,b]).getBounds(), { padding: [20,20] });
console.log("bounds");

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

const map = L.map("map").setView([-1.29, 36.82], 6);
L.tileLayer("https://tile.openstreetmap.org/{z}/{x}/{y}.png", { attribution: "© OSM" }).addTo(map);
L.marker([-1.29, 36.82]).addTo(map);
console.log("marker");