bringing npm packages to Guix

[zamfofex]

Hello, Guix!

A few months ago, I picked up the work towards importing npm packages to Guix 
by Jelle et al. in the hopes of continuing it, and I felt disheartened when I 
concluded that it does indeed seem like a very large part of npm is necessary 
to build even a simple package like jQuery.

But, recently, I decided to spend some more time thinking about it, and I 
realized that not all of the ‘devDependencies’ of a given package are actually 
necessary to build it. A lot of packages have ‘devDependencies’ for things such 
as tests and watching the filesystem for changes for ease of development.

If you think about it, what the vast majority of npm packages need to build 
successfully comes down to (optionally) compile TypeScript, then (optionally) 
perform some kind of bundling or transpilation. And that doesn’t really require 
TypeScript or a build tool from npm, since esbuild (which is already packaged) 
can do both of those things by itself.

Now, taking away the ‘devDependencies’ when recursing the dependency tree makes 
the whole endeavor of importing an npm package seem *much less* difficult and 
scary! The biggest unfortunate issue is that for packages with a build step 
(TypeScript and/or bundling+transpilation), it is necessary to use esbuild 
ad‐hoc (i.e. in a case-by-case basis), because each package has its own build 
peculiarities, and esbuild doesn’t acknowledge them. (One solution could be to 
create an esbuild wrapper that mimics ‘tsc’ and other tools.)

With that approach in mind, I was able to package sucrase as a proof of 
concept! Note that sucrase doesn’t have a lot of transitive dependencies, so it 
was easy to just modify the phases of each package in an ad‐hoc way. However, 
also note that sucrase depends on itself, so I decided to bootstrap it with 
esbuild, then use the bootstrapped version to build sucrase again. (The 
bootstrapped sucrase seems to also work as expected!)

The import script I wrote, alongside the sucrase package itself can be found 
here:
- <https://gist.github.com/zamfofex/eac93bc0e00477a8b79f5ca4dc1a34ff>

Any kinds of thoughts or feedback on this would be appreciated!

A few notes of potential future work:

- Keep tests on packages, after packaging the necessary test libraries.
- Maybe: Write a wrapper for esbuild for mimicking ‘tsc’ and other tools. (As 
mentioned above.)
- Figure out a way to detect vendored dependencies and other forms of bundles 
in repositories.
- Polish the import script, and make it fit Guix’ style and formatting 
practices.
- Use the ‘version’ variable in the source field of package definitions when 
importing. (An extension of the item above.)