We were writing theme-transpiler JS files to the filesystem on a per-process basis, and then immediately reading them back in. Plus, there was no cleanup mechanism, so the tmp directory would grow indefinitely.
This commit refactors things so that the `build.js` script outputs the theme-transpiler source to stdout. That way, we can read it directly into the process, and then into mini-racer, without needing to go via the filesystem. No cleanup required!
In production, the theme-transpiler is still cached in a file during `assets:precompile`
decorator-transforms (https://github.com/ef4/decorator-transforms) is a modern replacement for babel's plugin-proposal-decorators. It provides a decorator implementation using modern browser features, without needing to enable babel's full suite of class feature transformations. This improves the developer experience and performance.
In local testing with Google's 'tachometer' tool, this reduces Discourse's 'init-to-render' time by around 3-4% (230ms -> 222ms).
It reduces our initial gzip'd JS payloads by 3.2% (2.43MB -> 2.35MB), or 7.5% (14.5MB -> 13.4MB) uncompressed.
This was previously reverted in 97847f6. This version includes a babel transformation which works around the bug in Safari <= 15.
For Cloudflare compatibility issues, check https://meta.discourse.org/t/311390
This reverts commit 0f4520867b.
This has led to two problems:
1. An incompatibility with Cloudflare's "auto minify" feature. They've deprecated this feature because of incompatibility with modern JS syntax. But unfortunately it will remain enabled on existing properties until 2024-08-05.
2. Discourse fails to boot in Safari 15. This is strange, because Safari does support all the required features in our production JS bundles. Even more strangely, things start working as soon as you open the developer tools. That suggests the cause could be a Safari bug rather than a simple incompatibility.
Reverting while we work out a path forward on both those issues.
decorator-transforms (https://github.com/ef4/decorator-transforms) is a modern replacement for babel's plugin-proposal-decorators. It provides a decorator implementation using modern browser features, without needing to enable babel's full suite of class feature transformations. This improves the developer experience and performance.
In local testing with Google's 'tachometer' tool, this reduces Discourse's 'init-to-render' time by around 3-4% (230ms -> 222ms).
It reduces our initial gzip'd JS payloads by 3.2% (2.43MB -> 2.35MB), or 7.5% (14.5MB -> 13.4MB) uncompressed.
JS assets added by plugins via `register_asset` will be outside the `assets/javascripts` directory, and are therefore exempt from being transpiled. That means that there isn't really any need to run them through DiscourseJsProcessor. Instead, we can just concatenate them together, and avoid the need for all the sprockets-wrangling.
This commit also takes the opportunity to clean up a number of plugin-asset-related codepaths which are no longer required (e.g. globs, handlebars)
Reverts e2705df and re-lands #23187 and #23219.
The issue was incorrect order of execution of Rails' `assets:precompile` task in our own precompilation stack.
Co-authored-by: David Taylor <david@taylorhq.com>
Ember CLI will automatically run babel transformations in parallel when the config is 'serializable', and can therefore be applied in multiple processes automatically. If any plugin is defined in an unserializable way, parallelisation will be disabled.
Our discourse-widget-hbs transformer was causing parallelisation to be disabled. This commit fixes that, and also enables the throwUnlessParallelizable flag so that we catch this kind of issue more easily in future.
This commit also refactors our deprecation silencing system into its own file, and uses a fake babel plugin to ensure deprecations are silenced in babel worker processes.
In our GitHub CI jobs, this doubles the speed of ember builds (1m30s -> 45s). It should also improve production deploy times, and cold-start dev builds.
Theme javascript is now minified using Terser, just like our core/plugin JS bundles. This reduces the amount of data sent over the network.
This commit also introduces sourcemaps for theme JS. Browser developer tools will now be able show each source file separately when browsing, and also in backtraces.
For theme test JS, the sourcemap is inlined for simplicity. Network load is not a concern for tests.
Previously we were relying on a highly-customized version of the unmaintained Barber gem for theme template compilation. This commit switches us to use our own DiscourseJsProcessor, which makes use of more modern patterns and will be easier to maintain going forward.
In summary:
- Refactors DiscourseJsProcessor to move multiline JS heredocs into a companion `discourse-js-processor.js` file
- Use MiniRacer's `.call` method to avoid manually escaping JS strings
- Move Theme template AST transformers into DiscourseJsProcessor, and formalise interface for extending RawHandlebars AST transformations
- Update Ember template compilation to use a babel-based approach, just like Ember CLI. This gives each template its own ES6 module rather than directly assigning `Ember.TEMPLATES` values
- Improve testing of template compilation (and move some tests from `theme_javascript_compiler_spec.rb` to `discourse_js_processor_spec.rb`
This commit makes a number of improvements to the DiscourseJsProcessor:
1. Remove dependence on the out-of-date Ember template compiler from the ember-rails gem; switch to modern template compiler
2. Refactor to make use of a proper module system with `define`/`require`
3. Introduce `babel-plugin-ember-template-compilation` to enable inline hbs compilation
The `mini-loader` is upgraded to support relative lookup and `require.has`, so that these new JS packages work correctly.
The new plugin list is based on the ones currently used in our ember-cli pipeline, and are based on our official browser support policy.
This commit includes an update to the raw-handlebars compiler to remove the 'very hacky but lets us use ES6' code. It's served us well for the last 6 years, but the babel config changes broke it (`const` -> `let`). This commit takes the opportunity to refactor it to take a similar approach to PrettyText, by leaning on `mini-loader.js`.
Previously, accessing the Rails app directly in development mode would give you assets from our 'legacy' Ember asset pipeline. The only way to run with Ember CLI assets was to run ember-cli as a proxy. This was quite limiting when working on things which are bypassed when using the ember-cli proxy (e.g. changes to `application.html.erb`). Also, since `ember-auto-import` introduced chunking, visiting `/theme-qunit` under Ember CLI was failing to include all necessary chunks.
This commit teaches Sprockets about our Ember CLI assets so that they can be used in development mode, and are automatically collected up under `/public/assets` during `assets:precompile`. As a bonus, this allows us to remove all the custom manifest modification from `assets:precompile`.
The key changes are:
- Introduce a shared `EmberCli.enabled?` helper
- When ember-cli is enabled, add ember-cli `/dist/assets` as the top-priority Rails asset directory
- Have ember-cli output a `chunks.json` manifest, and teach `preload_script` to read it and append the correct chunks to their associated `afterFile`
- Remove most custom ember-cli logic from the `assets:precompile` step. Instead, rely on Rails to take care of pulling the 'precompiled' assets into the `public/assets` directory. Move the 'renaming' logic to runtime, so it can be used in development mode as well.
- Remove fingerprinting from `ember-cli-build`, and allow Rails to take care of things
Long-term, we may want to replace Sprockets with the lighter-weight Propshaft. The changes made in this commit have been made with that long-term goal in mind.
tldr: when you visit the rails app directly, you'll now be served the current ember-cli assets. To keep these up-to-date make sure either `ember serve`, or `ember build --watch` is running. If you really want to load the old non-ember-cli assets, then you should start the server with `EMBER_CLI_PROD_ASSETS=0`. (the legacy asset pipeline will be removed very soon)
To make this possible in development mode, the `sourceURL=` implementation needs to include something plugin-specific. This has no effect on production.
The asset version is bumped in order to trigger a re-compilation of plugin JS assets.
Per Google, sites are encouraged to upgrade from Universal Analytics v3 `analytics.js` to v4 `gtag.js` for Google Analytics tracking. We're giving admins the option to stay on the v3 API or migrate to v4. Admins can change the implementation they're using via the `ga_version` site setting. Eventually Google will deprecate v3, but our implementation gives admins the choice on what to use for now.
We chose this implementation to make the change less error prone, as many site admins are using custom events via the v3 UA API. With the site stetting defaulted to `v3_analytics`, site analytics won't break until the admin is ready to make the migration.
Additionally, in the v4 implementation, we do not enable automatic pageview tracking (on by default in the v4 API). Instead we rely on Discourse's page change API to report pageviews on transition to avoid double-tracking.
Creates a BabelHelper builder using a default list of plugins, to ensure the transpiled code is always using the same plugins instead of differents plugins in different cases.
* DEV: To be pedantic, there is more than EMBER in there now
* DEV: Use less globals. Have `Discourse` start in an initializer
* DEV: Remove another global
Prior to this change we would never clear memory from contexts and
rely on V8 reacting to pressure
This could lead to bloating of PrettyText and Transpiler contexts
This optimisations ensures that we will clear memory 2 seconds after
the last eval on the context
This is to help with the migration to Ember CLI. In the current running
version of Discourse everything should be the same as before, just with
a few extra files that are not used. However, using Ember CLI this can
be installed as an Ember addon.
Co-Authored-By: Jarek Radosz <jradosz@gmail.com>
This adds support for a new piece of metadata to your plugin.rb
files. If you add:
```
transpile_js: true
```
Then Discourse will support transpilation of assets in your
`assets/javascripts` directory. Previously they had to be named
`.js.es6` but now regular `.js` will work.
Note this is opt-in because some plugins currently have `.js` files in
app/assets that are not meant to be transpiled.
Going forward all plugins should migrate to this setting as they are
comfortable able to do so.
