const EventStation = require('event-station'); class Spaceship extends EventStation { launch(destination) { this.emit('launch', destination); } } let Normandy = new Spaceship(); let Tempest = new Spaceship(); // Add two listeners via a listener map let listeners = Normandy.on({ launch: (dest) => console.log(`Spaceship launched! En route to ${dest}.`), dock: () => console.log('Spaceship docking.'), }); // Attach the same listeners to Tempest that are on Normandy listeners.addTo(Tempest); // Launch Tempest when Normandy launches Tempest.hear(Normandy, 'launch') .once((dest) => Tempest.launch(dest)); // Launch both ships to the Andromeda Galaxy Normandy.launch('Messier 31'); // Stop listening to both ships listeners.off();