The WebSocket dependency of ActionCable.Connection was made configurable
in 66901c1849
However, the reference here in Connection#getState was not updated to
use the configurable property. This change remedies that and adds a test
to verify it. Additionally, it backfills a test to ensure that
Connection#open uses the configurable property.
* Replace several ActionCable.* references with finer-grained imports
This reduces the number of circular dependencies among the module
imports from 4:
```
(!) Circular dependency: app/javascript/action_cable/index.js -> app/javascript/action_cable/connection.js -> app/javascript/action_cable/index.js
(!) Circular dependency: app/javascript/action_cable/index.js -> app/javascript/action_cable/connection_monitor.js -> app/javascript/action_cable/index.js
(!) Circular dependency: app/javascript/action_cable/index.js -> app/javascript/action_cable/consumer.js -> app/javascript/action_cable/index.js
(!) Circular dependency: app/javascript/action_cable/index.js -> app/javascript/action_cable/subscriptions.js -> app/javascript/action_cable/index.js
```
to 2:
```
(!) Circular dependency: app/javascript/action_cable/index.js -> app/javascript/action_cable/connection.js -> app/javascript/action_cable/index.js
(!) Circular dependency: app/javascript/action_cable/index.js -> app/javascript/action_cable/connection.js -> app/javascript/action_cable/connection_monitor.js -> app/javascript/action_cable/index.js
```
* Remove tests that only test javascript object property assignment
These tests really only assert that you can assign a property to
the ActionCable global object. That's true for pretty much any object
in javascript (it would only be false if the object has been frozen, or
has explicitly set some properties to be nonconfigurable).
* Refactor ActionCable to provide individual named exports
By providing individual named exports rather than a default export which
is an object with all of those properties, we enable applications to
only import the functions they need: any unused functions will be
removed via tree shaking.
Additionally, this restructuring removes the remaining circular
dependencies by extracting the separate adapters and logger modules, so
there are now no warnings when compiling the ActionCable bundle.
Note: This produces two small breaking API changes:
- The `ActionCable.WebSocket` getter and setter would be moved to
`ActionCable.adapters.WebSocket`. If a user is currently configuring
this, when upgrading they'd need to either add a delegated
getter/setter themselves, or change it like this:
```diff
- ActionCable.WebSocket = MyWebSocket
+ ActionCable.adapters.WebSocket = MyWebSocket
```
Applications which don't change the WebSocket adapter would not need
any changes for this when upgrading.
- Similarly, the `ActionCable.logger` getter and setter would be moved
to `ActionCable.adapters.logger`. If a user is currently configuring
this, when upgrading they'd need to either add a delegated
getter/setter themselves, or change it like this:
```diff
- ActionCable.logger = myLogger
+ ActionCable.adapters.logger = myLogger
```
Applications which don't change the logger would not need any changes
for this when upgrading.
These two aspects of the public API have to change because there's no
way to export a property setter for `WebSocket` (or `logger`) such that
this:
```js
import ActionCable from "actioncable"
ActionCable.WebSocket = MyWebSocket
```
would actually update `adapters.WebSocket`. (We can only offer that if
we have two separate source files like if `index.js` uses
`import * as ActionCable from "./action_cable" and then exports a
wrapper which has delegated getters and setters for those properties.)
This API change is very minor - it should be easy for applications to
add the `adapters.` prefix in their assignments or to patch in delegated
setters. And especially because most applications in the wild are not
ever changing the default value of `ActionCable.WebSocket` or
`ActionCable.logger` (because the default values are perfect), this API
breakage is worth the tree-shaking benefits we gain.
* Include source code in published actioncable npm package
This allows actioncable users to ship smaller javascript bundles to
visitors using modern browsers, as demonstrated in this repository:
https://github.com/rmacklin/actioncable-es2015-build-example
In that example, the bundle shrinks by 2.8K (25.2%) when you simply
change the actioncable import to point to the untranspiled src.
If you go a step further, like this:
```
diff --git a/app/scripts/main.js b/app/scripts/main.js
index 17bc031..1a2b2e0 100644
--- a/app/scripts/main.js
+++ b/app/scripts/main.js
@@ -1,6 +1,6 @@
-import ActionCable from 'actioncable';
+import * as ActionCable from 'actioncable';
let cable = ActionCable.createConsumer('wss://cable.example.com');
cable.subscriptions.create('AppearanceChannel', {
```
then the bundle shrinks by 3.6K (31.7%)!
In addition to allowing smaller bundles for those who ship untranspiled
code to modern browsers, including the source code in the published
package can be useful in other ways:
1. Users can import individual modules rather than the whole library
2. As a result of (1), users can also monkey patch parts of actioncable
by importing the relevant module, modifying the exported object, and
then importing the rest of actioncable (which would then use the
patched object).
Note: This is the same enhancement that we made to activestorage in
c0368ad090
* Remove unused commonjs & resolve plugins from ActionCable rollup config
These were added when we copied the rollup config from ActiveStorage,
but ActionCable does not have any commonjs dependencies (it doesn't have
any external dependencies at all), so these plugins are unnecessary here
* Change ActionCable.startDebugging() -> ActionCable.logger.enabled=true
and ActionCable.stopDebugging() -> ActionCable.logger.enabled=false
This API is simpler and more clearly describes what it does
* Change Travis configuration to run yarn install at the root for ActionCable builds
This is necessary now that the repository is using Yarn Workspaces
We've replaced the sprockets `//= require` directives with ES2015
imports. As a result, the ActionCable javascript can now be compiled
with rollup (like ActiveStorage already is).
- Rename action_cable/index.js.erb -> action_cable/index.js
- Add rake task to generate a javascript module of the ActionCable::INTERNAL ruby hash
This will allow us to get rid of ERB from the actioncable javascript,
since it is only used to interpolate ActionCable::INTERNAL.to_json.
- Import INTERNAL directly in ActionCable Connection module
This is necessary to remove a load-order dependency conflict in the
rollup-compiled build. Using ActionCable.INTERNAL would result in a
runtime error:
```
TypeError: Cannot read property 'INTERNAL' of undefined
```
because ActionCable.INTERNAL is not set before the Connection module
is executed.
All other ActionCable.* references are executed inside of the body of a
function, so there is no load-order dependency there.
- Add eslint and eslint-plugin-import devDependencies to actioncable
These will be used to add a linting setup to actioncable like the one
in activestorage.
- Add .eslintrc to actioncable
This lint configuration was copied from activestorage
- Add lint script to actioncable
This is the same as the lint script in activestorage
- Add babel-core, babel-plugin-external-helpers, and babel-preset-env devDependencies to actioncable
These will be used to add ES2015 transpilation support to actioncable
like we have in activestorage.
- Add .babelrc to actioncable
This configuration was copied from activestorage
- Enable loose mode in ActionCable's babel config
This generates a smaller bundle when compiled
- Add rollup devDependencies to actioncable
These will be used to add a modern build pipeline to actioncable like
the one in activestorage.
- Add rollup config to actioncable
This is essentially the same as the rollup config from activestorage
- Add prebuild and build scripts to actioncable package
These scripts were copied from activestorage
- Invoke code generation task as part of actioncable's prebuild script
This will guarantee that the action_cable/internal.js module is
available at build time (which is important, because two other modules
now depend on it).
- Update actioncable package to reference the rollup-compiled files
Now that we have a fully functional rollup pipeline in actioncable, we
can use the compiled output in our npm package.
- Remove build section from ActionCable blade config
Now that rollup is responsible for building ActionCable, we can remove
that responsibility from Blade.
- Remove assets:compile and assets:verify tasks from ActionCable
Now that we've added a compiled ActionCable bundle to version control,
we don't need to compile and verify it at publish-time.
(We're following the pattern set in ActiveStorage.)
- Include compiled ActionCable javascript bundle in published gem
This is necessary to maintain support for depending on the ActionCable
javascript through the Sprockets asset pipeline.
- Add compiled ActionCable bundle to version control
This mirrors what we do in ActiveStorage, and allows ActionCable to
continue to be consumed via the sprockets-based asset pipeline when
using a git source instead of a published version of the gem.
