@fleetbase/leaflet-routing-machine/examples/index.js

ESM module Routing for Leaflet

var map = L.map('map');

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

var control = L.Routing.control(L.extend(window.lrmConfig, {
	waypoints: [
		L.latLng(57.74, 11.94),
		L.latLng(57.6792, 11.949)
	],
	geocoder: L.Control.Geocoder.nominatim(),
	routeWhileDragging: true,
	reverseWaypoints: true,
	showAlternatives: true,
	altLineOptions: {
		styles: [
			{color: 'black', opacity: 0.15, weight: 9},
			{color: 'white', opacity: 0.8, weight: 6},
			{color: 'blue', opacity: 0.5, weight: 2}
		]
	}
})).addTo(map);

L.Routing.errorControl(control).addTo(map);