Rails 5 ActionCable App is not defined

Question

I am new to ActionCable in Rails 5. I am trying to make a chat for my Rails app. When I try and send a test message through the console App.room.speak('Test!') but when I do I get an error.

Uncaught ReferenceError: App is not defined at :1:1

room.coffe

App.room = App.cable.subscriptions.create "RoomChannel",
  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
  $('message').append data

  speak: (message)->
  @perform 'speak', message: message

room_channel.rb

class RoomChannel < ApplicationCable::Channel
   def subscribed
     stream_from "room_channel"
   end

   def unsubscribed
      # Any cleanup needed when channel is unsubscribed
   end

   def speak (data)
     Message.new content: data['message'], user: current_user
   end
end

broadcast_message_job.rb

class BroadcastMessageJobJob < ApplicationJob
   queue_as :default

   def perform(meesage)
     ActionCable.server.broadcast 'room_channel', render_message(message)
   end

   private

   def render_message(message)
     ApplicationController.renderer.render message
   end
end

cable.js

(function() {
   this.App || (this.App = {});

   App.cable = ActionCable.createConsumer();

}).call(this);

routes.rb

mount ActionCable.server => '/cable'

Lacylad

Answer 1

Make sure you've added the require_self in the cable.js file:

// app/assets/javascripts/cable.js
//= require action_cable
//= require_self
//= require_tree ./channels

(function() {
  this.App || (this.App = {});
  App.cable = ActionCable.createConsumer();
}).call(this);

This will add the content from this same cable.js file, if you've defined the App in other file, then you'll need to add it in the "require" section.

Interpellation

Does js file load order matter when it comes defining App? If the same anonymous function was in another file then wouldn't it have the same result of either using this.App if it's already been declared or otherwise set it to an empty object and begin using it? – Hirsute