The `decodedMap` prop comes from https://github.com/terser/terser/pull/1190
> This also exposes a new `decodedMap` property on the result object. Decoded maps are free to create (it's a shallow clone of the `GenMapping` instance), and passing them to `@jridgewell/trace-mapping` is copy-free. With Babel [recently](https://github.com/babel/babel/pull/14497) adding a `decodedMap` field, a dev could pass from the Babel transpilation to Terser without any added memory use for sourcemaps.
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 Remove dependence on the out-of-date Ember template compiler from the ember-rails gem; switch to modern template compiler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.
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
* Remove some `.es6` from comments where it does not matter
* Use a post processor for transpilation
This will allow us to eventually use the directory structure to
transpile rather than the extension.
* FIX: Some errors and clean up in confirm-new-email
It would throw an error if the webauthn element wasn't present.
Also I changed things so that no-module is not explicitly
referenced.
* Remove `no-module`
Instead we allow a magic comment: `// discourse-skip-module` to prevent
the asset pipeline from creating a module.
* DEV: Enable babel transpilation based on directory
If it's in `app/assets/javascripts/dicourse` it will be transpiled
even without the `.es6` extension.
* REFACTOR: Remove Tilt/ES6ModuleTranspiler
David Taylor
Jarek Radosz
dependabot[bot]
Phil Pirozhkov
Robin Ward