This allows us to remove the manually implemented `structuredClone` polyfill, thus reducing the maintenance burden for the `LoopbackPort` class; refer to https://github.com/zloirock/core-js#structuredclone
*Please note:* While `structuredClone` support landed already in Firefox 94, Google Chrome only added it in version 98 (currently in Beta). However, given that the `LoopbackPort` will only be used together with *fake workers* in browsers this shouldn't be too much of a problem.[1]
For Node.js environments, where *fake workers* are unfortunately necessary, using a `legacy/`-build is already required which thus guarantees that the `structuredClone` polyfill is available.
Also, the patch updates core-js to the latest version since that one includes `structuredClone` improvements; please see https://github.com/zloirock/core-js/releases/tag/v3.20.3
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[1] Given that we only support browsers with proper worker support, if *fake workers* are being used that essentially indicates a configuration problem/error.
This patch circumvents the issues seen when trying to update TypeScript to version `4.5`, by "simply" fixing the broken/missing JSDocs and `typedef`s such that `gulp typestest` now passes.
As always, given that I don't really know anything about TypeScript, I cannot tell if this is a "correct" and/or proper way of doing things; we'll need TypeScript users to help out with testing!
*Please note:* I'm sorry about the size of this patch, but given how intertwined all of this unfortunately is it just didn't seem easy to split this into smaller parts.
However, one good thing about this TypeScript update is that it helped uncover a number of pre-existing bugs in our JSDocs comments.
With ESLint 8 we should now finally be able to start using modern `class` features, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Public_class_fields and https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Private_class_fields
However, while both ESLint and Acorn now support this, it unfortunately turns out that Escodegen (which we use during building) still lack the necessary support. Looking at https://github.com/estools/escodegen there's not been any updates since last year, and there's also open PRs adding support for these new `class` features.
To avoid blocking usage of these `class` features in the PDF.js code-base, in particular *private* fields/methods, this patch thus proposes that we (hopefully temporarily) switch to an `escodegen` fork that has the necessary support; please see https://www.npmjs.com/package/@javascript-obfuscator/escodegen
While I have no reason to doubt the security of the `escodegen` fork, this patch nonetheless pins the version number. Furthermore, I've also diffed the output of the two `.js`-files in this forked package against the original files without finding anything that looks immediately "dangerous".
This command was added all the way back when basic CI-support was first introduced (using Travis at the time), however it's never really intended to be used e.g. for local development.
By having a `npm test`-command listed in the `package.json` file, there's a very real risk that someone unfamiliar with the code-base would only run that one and thus miss all the other (more important) test-suites[1].
Hence this patch which removes the `npm test`-command, and instead simply calls the relevant gulp-task[2] directly in the GitHub Actions configuration.
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[1] Which consist of the unit-tests (run in browsers), the font-tests (potentially), the reference-tests, and the integration-tests.
[2] Which is also renamed slightly, to better fit its current usage.
According to https://docs.npmjs.com/cli/v7/configuring-npm/package-json#version, the "version" field is not required[1]:
> If you don't plan to publish your package, the name and version fields are optional.
Hence it shouldn't be necessary to have a "dummy" `version` field in the `package.json` file, and it seems quite unfortunate to have an essentially meaningless entry in that file.[2]
Furthermore, I'd even go as far as suggesting that it's actually doing more harm than good in practice, since it's not uncommon for people to open issues where they simply quote the `package.json`-entry when filling out the ISSUE_TEMPLATE thus causing confusion as to which *exact* version is actually used.
Unless I'm misremembering, I believe that the only reason for adding the `version` field was that is was necessary in order for things to work back when testing was run on Travis.
Now we're using GitHub Actions instead, where things seem to work just find even without a `version` field; hence why I think it makes sense to remove this.
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[1] Please note that this patch doesn't affect the `pdfjs-dist` package, since the `package.json` file used there is created in `gulpfile.js` during building.
[2] Trying to, automatically, update the `version` field on *every* commit really doesn't seem worth it to me.
By adding basic linting of JSON files, we can ensure that they're actually valid and prevent e.g. test-failures caused by *accidental* errors when editing the `test/test_manifest.json` file (something that I've done *many* times myself).
For now this simply uses the `recommended` configuration, but we can obviously tweak this later if/when needed. Please find additional information at https://github.com/azeemba/eslint-plugin-json
