forgeplus/app/assets/javascripts/channels/mirror_project.js

App.mirror_project = App.cable.subscriptions.create("MirrorProjectChannel", {
  connected: function() {
    // Called when the subscription is ready for use on the server
  },

  disconnected: function() {
    // Called when the subscription has been terminated by the server
  },

  received: function(data) {
    // Called when there's incoming data on the websocket for this channel
  }
});