7 files changed, 71 insertions, 23 deletions
diff --git a/guides/source/6_0_release_notes.md b/guides/source/6_0_release_notes.md
index 14528d1cde..e6fb15c09c 100644
--- a/guides/source/6_0_release_notes.md
+++ b/guides/source/6_0_release_notes.md
@@ -92,6 +92,22 @@ Please refer to the [Changelog][action-cable] for detailed changes.
 
 ### Notable changes
 
+*   The ActionCable javascript package has been converted from CoffeeScript
+    to ES2015, and we now publish the source code in the npm distribution.
+
+    This allows ActionCable users to depend on the javascript source code
+    rather than the compiled code, which can produce smaller javascript bundles.
+
+    This change includes some breaking changes to optional parts of the
+    ActionCable javascript API:
+
+    - Configuration of the WebSocket adapter and logger adapter have been moved
+      from properties of `ActionCable` to properties of `ActionCable.adapters`.
+
+    - The `ActionCable.startDebugging()` and `ActionCable.stopDebugging()`
+      methods have been removed and replaced with the property
+      `ActionCable.logger.enabled`.
+
 Action Pack
 -----------
 
diff --git a/guides/source/action_cable_overview.md b/guides/source/action_cable_overview.md
index df02d5bd91..8f5c44849a 100644
--- a/guides/source/action_cable_overview.md
+++ b/guides/source/action_cable_overview.md
@@ -181,9 +181,9 @@ established using the following JavaScript, which is generated by default by Rai
 // 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.
 
-import ActionCable from "@rails/actioncable"
+import { createConsumer } from "@rails/actioncable"
 
-export default ActionCable.createConsumer()
+export default createConsumer()
 ```
 
 This will ready a consumer that'll connect against `/cable` on your server by default.
diff --git a/guides/source/active_storage_overview.md b/guides/source/active_storage_overview.md
index 6d07d34dd7..474a93c83e 100644
--- a/guides/source/active_storage_overview.md
+++ b/guides/source/active_storage_overview.md
@@ -489,8 +489,7 @@ directly from the client to the cloud.
     Using the npm package:
 
     ```js
-    import * as ActiveStorage from "@rails/activestorage"
-    ActiveStorage.start()
+    require("@rails/activestorage").start()
     ```
 
 2. Annotate file inputs with the direct upload URL.
diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md
index 4f3e8b2cff..38e46e4bf8 100644
--- a/guides/source/association_basics.md
+++ b/guides/source/association_basics.md
@@ -1257,7 +1257,7 @@ Controls what happens to the associated object when its owner is destroyed:
 
 * `:destroy` causes the associated object to also be destroyed
 * `:delete` causes the associated object to be deleted directly from the database (so callbacks will not execute)
-* `:nullify` causes the foreign key to be set to `NULL`. Callbacks are not executed.
+* `:nullify` causes the foreign key to be set to `NULL`. Polymorphic type column is also nullified on polymorphic associations. Callbacks are not executed.
 * `:restrict_with_exception` causes an `ActiveRecord::DeleteRestrictionError` exception to be raised if there is an associated record
 * `:restrict_with_error` causes an error to be added to the owner if there is an associated object
 
@@ -1658,7 +1658,7 @@ Controls what happens to the associated objects when their owner is destroyed:
 
 * `:destroy` causes all the associated objects to also be destroyed
 * `:delete_all` causes all the associated objects to be deleted directly from the database (so callbacks will not execute)
-* `:nullify` causes the foreign keys to be set to `NULL`. Callbacks are not executed.
+* `:nullify` causes the foreign key to be set to `NULL`. Polymorphic type column is also nullified on polymorphic associations. Callbacks are not executed.
 * `:restrict_with_exception` causes an `ActiveRecord::DeleteRestrictionError` exception to be raised if there are any associated records
 * `:restrict_with_error` causes an error to be added to the owner if there are any associated objects
 
diff --git a/guides/source/engines.md b/guides/source/engines.md
index c4829299ca..f15383e3f1 100644
--- a/guides/source/engines.md
+++ b/guides/source/engines.md
@@ -1091,16 +1091,15 @@ main Rails application.
 Engine model and controller classes can be extended by open classing them in the
 main Rails application (since model and controller classes are just Ruby classes
 that inherit Rails specific functionality). Open classing an Engine class
-redefines it for use in the main application. This is usually implemented by
-using the decorator pattern.
+redefines it for use in the main application.
 
 For simple class modifications, use `Class#class_eval`. For complex class
 modifications, consider using `ActiveSupport::Concern`.
 
-#### A note on Decorators and Loading Code
+#### A note on Overriding and Loading Code
 
-Because these decorators are not referenced by your Rails application itself,
-Rails' autoloading system will not kick in and load your decorators. This means
+Because these overrides are not referenced by your Rails application itself,
+Rails' autoloading system will not kick in and load your overrides. This means
 that you need to require them yourself.
 
 Here is some sample code to do this:
@@ -1112,7 +1111,7 @@ module Blorgh
     isolate_namespace Blorgh
 
     config.to_prepare do
-      Dir.glob(Rails.root + "app/decorators/**/*_decorator*.rb").each do |c|
+      Dir.glob(Rails.root + "app/overrides/**/*_override*.rb").each do |c|
         require_dependency(c)
       end
     end
@@ -1120,15 +1119,15 @@ module Blorgh
 end
 ```
 
-This doesn't apply to just Decorators, but anything that you add in an engine
+This doesn't apply to just overrides, but anything that you add in an engine
 that isn't referenced by your main application.
 
-#### Implementing Decorator Pattern Using Class#class_eval
+#### Reopening existing classes using Class#class_eval
 
 **Adding** `Article#time_since_created`:
 
 ```ruby
-# MyApp/app/decorators/models/blorgh/article_decorator.rb
+# MyApp/app/overrides/models/blorgh/article_override.rb
 
 Blorgh::Article.class_eval do
   def time_since_created
@@ -1149,7 +1148,7 @@ end
 **Overriding** `Article#summary`:
 
 ```ruby
-# MyApp/app/decorators/models/blorgh/article_decorator.rb
+# MyApp/app/overrides/models/blorgh/article_override.rb
 
 Blorgh::Article.class_eval do
   def summary
@@ -1169,7 +1168,7 @@ class Article < ApplicationRecord
 end
 ```
 
-#### Implementing Decorator Pattern Using ActiveSupport::Concern
+#### Reopening existing classes using ActiveSupport::Concern
 
 Using `Class#class_eval` is great for simple adjustments, but for more complex
 class modifications, you might want to consider using [`ActiveSupport::Concern`]
diff --git a/guides/source/testing.md b/guides/source/testing.md
index 576c4d768c..1a2f480407 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -1735,14 +1735,14 @@ Testing Action Cable
 --------------------
 
 Since Action Cable is used at different levels inside your application,
-you'll need to test both the channels and connection classes themsleves and that other
+you'll need to test both the channels, connection classes themselves, and that other
 entities broadcast correct messages.
 
 ### Connection Test Case
 
 By default, when you generate new Rails application with Action Cable, a test for the base connection class (`ApplicationCable::Connection`) is generated as well under `test/channels/application_cable` directory.
 
-Connection tests aim to check whether a connection's identifiers gets assigned properly
+Connection tests aim to check whether a connection's identifiers get assigned properly
 or that any improper connection requests are rejected. Here is an example:
 
 ```ruby
@@ -1765,9 +1765,8 @@ end
 
 You can also specify request cookies the same way you do in integration tests:
 
-
 ```ruby
-test "connects with_cookies" do
+test "connects with cookies" do
   cookies.signed[:user_id] = "42"
 
   connect
@@ -1778,7 +1777,6 @@ end
 
 See the API documentation for [`AcionCable::Connection::TestCase`](http://api.rubyonrails.org/classes/ActionCable/Connection/TestCase.html) for more information.
 
-
 ### Channel Test Case
 
 By default, when you generate a channel, an associated test will be generated as well
@@ -1823,7 +1821,7 @@ See the API documentation for [`AcionCable::Channel::TestCase`](http://api.rubyo
 
 Action Cable ships with a bunch of custom assertions that can be used to lessen the verbosity of tests. For a full list of available assertions, see the API documentation for [`ActionCable::TestHelper`](http://api.rubyonrails.org/classes/ActionCable/TestHelper.html).
 
-It's a good practice to ensure that the correct message has been broadcasted inside another components (e.g. inside your controllers). This is precisely where
+It's a good practice to ensure that the correct message has been broadcasted inside other components (e.g. inside your controllers). This is precisely where
 the custom assertions provided by Action Cable are pretty useful. For instance,
 within a model:
 
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 2682c6ffd7..1f30ce1971 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -97,6 +97,42 @@ If you require your cookies to be read by 5.2 and older, or you are still valida
 to allow you to rollback set
 `Rails.application.config.action_dispatch.use_cookies_with_metadata` to `false`.
 
+### ActionCable javascript API Changes
+
+The ActionCable javascript package has been converted from CoffeeScript
+to ES2015, and we now publish the source code in the npm distribution.
+
+This change includes some breaking changes to optional parts of the
+ActionCable javascript API:
+
+- Configuration of the WebSocket adapter and logger adapter have been moved
+  from properties of `ActionCable` to properties of `ActionCable.adapters`.
+  If you are currently configuring these adapters you will need to make
+  these changes when upgrading:
+
+  ```diff
+  -    ActionCable.WebSocket = MyWebSocket
+  +    ActionCable.adapters.WebSocket = MyWebSocket
+  ```
+  ```diff
+  -    ActionCable.logger = myLogger
+  +    ActionCable.adapters.logger = myLogger
+  ```
+
+- The `ActionCable.startDebugging()` and `ActionCable.stopDebugging()`
+  methods have been removed and replaced with the property
+  `ActionCable.logger.enabled`. If you are currently using these methods you
+  will need to make these changes when upgrading:
+
+  ```diff
+  -    ActionCable.startDebugging()
+  +    ActionCable.logger.enabled = true
+  ```
+  ```diff
+  -    ActionCable.stopDebugging()
+  +    ActionCable.logger.enabled = false
+  ```
+
 Upgrading from Rails 5.1 to Rails 5.2
 -------------------------------------