A leaflet plugin for drawing routes on seas between two given points, using elfalem's Leaflet.curve and bgrin's javascript-astar.
// Define coordinates
var source = [0,0];
var destination = [-37, 37];
// Get visuals or the array of the path
var curve = L.pathCurve(source, destination);
var path = L.route(source, destination);
// Add to map
curve.addTo(map);
Route drawn for (-5, 67) => (58, -27):