add CJS bundle highlight.js/compat

[aduh95]

Refs: #2 (comment)

Changes

Checklist

• Added markup tests, or they don't apply here because...
• Updated the changelog at CHANGES.md

[joshgoebel]

Wouldn't buildNodeLanguage also have to be updated/suplimented to build all the individual languages in CJS?

[aduh95]

It depends, we could decide that we supply only a bundle CJS file – or we can go the dual module package way and provide a CJS module for each language, but I thought you said that was not acceptable?

[joshgoebel]

Can you not use type:module with conditional exports? I'm trying:

  7   "exports": {
  6     ".": {
  5       "require": "./compat.cjs",
  4       "import": "./lib/index.js"
  3     },
  2     "./lib/index": {
  1       "require": "./compat.cjs",
44        "import": "./lib/index.js"
  1     }
  2   },

But still require "./build" blows up saying I can't require an ESM module.

[aduh95]

Conditional exports work whether or not you set a "type" field in your package.json; however, the export map is used only when you require/import the package by name – so require("./build") will not use the export map because ./build is a directory path, not a package name.

To test the conditional exports, the "right thing to do" is to use a self-reference to highlight.js: https://nodejs.org/api/packages.html#packages_self_referencing_a_package_using_its_name

// root package.json
{
  "name": "highlight.js",
  "private": true,
  "exports": {
       ".": {
         "require": "./build/compat.cjs",
         "import": "./build/lib/index.js"
       },
       "./lib/index": {
         "require": "./build/compat.cjs",
         "import": "./build/lib/index.js"
       },
       "./lib/languages/*": "./build/lib/languages/*.js"
     }
}

// build/package.json
{
  "name": "highlight.js",
  "type": "module",
  "exports": {
       ".": {
         "require": "./compat.cjs",
         "import": "./lib/index.js"
       },
       "./lib/index": {
         "require": "./compat.cjs",
         "import": "./lib/index.js"
       },
       "./lib/languages/*": "./lib/languages/*.js"
     }
}

Hopefully that makes sense, let me know if that's not clear.

[joshgoebel]

Ok that works... but... Ugh, there has got to be some better way to test the built package asset independently of its source...

Because this doesn't depend on the build package.json at all. I never even modified it and this still works, so it's not really testing anything at all other than the source package.json.

How is one supposed to properly test conditional requires of a fully built package in a CI environment, etc?

I feel like we need a way to install the newly built package itself via npm and then run tests (or binary stubs) against that by name... am I thinking wrong here?

[aduh95]

I feel like we need a way to install the newly built package itself via npm and then run tests (or binary stubs) against that by name... am I thinking wrong here?

Yep, that's probably necessary as an integration test to run in the CI. For local testing, having the root package.json linking to the build folder is probably enough though.

[joshgoebel]

It seems you can do this with npm install directory:

npm init
npm install ../highlight.js/build/
# run tests in the scope of your new package (by name)