Generate `cable.js` file if does not exist when generating channel

- Before this, while generating a channel, we were not creating
  `cable.js` if it does not already exist.
- We have similar code for application mailer here -
  https://github.com/rails/rails/commit/0b3ae023d27197417541932632055cd6be4810c4.
- Based on the comment -
  https://github.com/rails/rails/issues/24418#issuecomment-205421995.

1 files changed, 13 insertions, 0 deletions

diff --git a/actioncable/lib/rails/generators/channel/templates/assets/cable.js b/actioncable/lib/rails/generators/channel/templates/assets/cable.js
new file mode 100644
index 0000000000..71ee1e66de
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/assets/cable.js
@@ -0,0 +1,13 @@
+// Action Cable provides the framework to deal with WebSockets in Rails.
+// You can generate new channels where WebSocket features live using the rails generate channel command.
+//
+//= require action_cable
+//= require_self
+//= require_tree ./channels
+
+(function() {
+  this.App || (this.App = {});
+
+  App.cable = ActionCable.createConsumer();
+
+}).call(this);