in Connection#close. We can do this because `isActive()` can only
return `true` if `this.webSocket` is truthy. (We can't have an active
connection without having instantiated a WebSocket. This is confirmed
in the code: Connection#isActive calls Connection#isState which calls
Connection#getState, which checks if `this.webSocket` is truthy and
returns `null` otherwise.)
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.
- Remove unnecessary Array.from usages from subscriptions.js
These were all Arrays before, so Array.from is a no-op
- Remove unnecessary IIFEs from subscriptions.js
- Manually decaffeinate sample ActionCable code in comments
Here the coffeescript -> ES2015 conversion was done by hand rather than
using decaffeinate, because these code samples were simple enough.
- Refactor ActionCable.Subscription to avoid initClass
- Refactor ActionCable.Subscription to use ES2015 default parameters
- Refactor ActionCable.ConnectionMonitor to avoid initClass
- Refactor ActionCable.ConnectionMonitor to use shorter variations of null checks
- Remove unnecessary code created because of implicit returns in ConnectionMonitor
This removes the `return` statements that were returning the value of
console.log and those from private methods whose return value was not
being used.
- Refactor ActionCable.Connection to avoid initClass
- Refactor Connection#isProtocolSupported and #isState
This addresses these three decaffeinate cleanup suggestions:
- DS101: Remove unnecessary use of Array.from
- DS104: Avoid inline assignments
- DS204: Change includes calls to have a more natural evaluation order
It also removes the use of Array.prototype.includes, which means we
don't have to worry about providing a polyfill or requiring that end
users provide one.
- Refactor ActionCable.Connection to use ES2015 default parameters
- Refactor ActionCable.Connection to use shorter variations of null checks
- Remove return statements that return the value of console.log() in ActionCable.Connection
- Simplify complex destructure assignment in connection.js
decaffeinate had inserted
```
adjustedLength = Math.max(protocols.length, 1)
```
to be safe, but we know that there has to always be at least one
protocol, so we don't have to worry about protocols.length being 0 here.
- Refactor Connection#getState
The decaffeinate translation of this method was not very clear, so we've
rewritten it to be more natural.
- Simplify destructure assignment in connection.js
- Remove unnecessary use of Array.from from action_cable.js.erb
- Refactor ActionCable#createConsumer and #getConfig
This addresses these two decaffeinate cleanup suggestions:
- DS104: Avoid inline assignments
- DS207: Consider shorter variations of null checks
- Remove unnecessary code created because of implicit returns in action_cable.js.erb
This removes the `return` statements that were returning the value of
console.log and those from methods that just set and unset the
`debugging` flag.
- Remove decaffeinate suggestion about avoiding top-level this
In this case, the top-level `this` is intentional, so it's okay to
ignore this suggestion.
- Remove decaffeinate suggestions about removing unnecessary returns
I did remove some of the return statements in previous commits, where
it seemed appropriate. However, the rest of these should probably remain
because the return values have been exposed through the public API. If
we want to break that contract, we can do so, but I think it should be
done deliberately as part of a breaking-API change (separate from this
coffeescript -> ES2015 conversion)
- Remove unused `unsupportedProtocol` variable from connection.js
Leaving this would cause eslint to fail
- Refactor Subscriptions methods to avoid `for` ... `of` syntax
Babel transpiles `for` ... `of` syntax to use `Symbol.iterator`, which
would require a polyfill in applications that support older browsers.
The `for` ... `of` syntax was produced by running `decaffeinate`, but in
these instances a simpler `map` should be sufficient and avoid any
`Symbol` issues.
Using [decaffeinate], we have converted these files from coffeescript
syntax to ES2015 syntax. Decaffeinate is very conservative in the
conversion process to ensure exact coffeescript semantics are preserved.
Most of the time, it's safe to clean up the code, and decaffeinate has
left suggestions regarding potential cleanups we can take. I'll tackle
those cleanups separately.
After running decaffeinate, I ran:
```
eslint --fix app/javascript
```
using the eslint configuration from ActiveStorage to automatically
correct lint violations in the decaffeinated output. This removed 189
extra semicolons and changed one instance of single quotes to double
quotes.
Note: decaffeinate and eslint can't parse ERB syntax. So I worked around
that by temporarily quoting the ERB:
```diff
@ActionCable =
- INTERNAL: <%= ActionCable::INTERNAL.to_json %>
+ INTERNAL: "<%= ActionCable::INTERNAL.to_json %>"
WebSocket: window.WebSocket
logger: window.console
```
and then removing those quotes after running decaffeinate and eslint.
[decaffeinate]: https://github.com/decaffeinate/decaffeinate
- Rename action_cable/*.coffee -> *.js
- Move app/assets/javascripts/* -> app/javascript/*
- Rename action_cable.js.erb -> action_cable/index.js.erb
Renaming the extension to .js is in preparation for converting these
files from coffeescript to ES2015.
Moving the files to app/javascript and putting the entry point in
index.js.erb changes the structure of ActionCable's javascript to match
the structure of ActiveStorage's javascript.
(We are doing the file moving and renaming in a separate commit to
ensure that the git history of the files will be preserved - i.e. git
will track these as file renames rather than unrelated file
additions/deletions. In particular, git blame will still trace back to
the original authorship.)
2018-11-02 08:40:10 -07:00
Renamed from actioncable/app/assets/javascripts/action_cable/connection.coffee (Browse further)
