channel.coffee

App.chat = App.cable.subscriptions.create "ChatChannel",
  connected: ->
    # Called when the subscription is ready for use on the server

  disconnected: ->
    # Called when the subscription has been terminated by the server

  received: (data) ->
    # Called when there's incoming data on the websocket for this channel

  speak: ->
    @perform 'speak'

channel.js

(function() {
  App.chat = App.cable.subscriptions.create("ChatChannel", {
    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
    },

    speak: function() {
      return this.perform('speak');
    }
  });
}).call(this)