feat: esm and cjs builds for node and browser

[diegomura]

Hi @devongovett ! Hope you are doing good.

I'd like to start using foliojs packages again in react-pdf. I gradually moved away from them due to several reasons, among them because node deps in foliojs repos. This includes pdfkit and png-js.

Here's my fork. This is the same node entrypoint here but bundled with rollup to generate node and browser entrypoints. Node ones are just like the existing ones. For browser though, we remove fs dependency and ignore methods that use it, and replace zlib with browserify-zlib.

Not sure who's responsible of reviewing and publishing (I have merge rights here, but not publishing to npm) but this first step would be very helpful towards start unifying foliojs with react-pdf 😄

[blikblum]

Instead of using non standard browser field, use nested conditions in exports field:
https://nodejs.org/api/packages.html#nested-conditions

IMO, for browser should have only import (es module)

This should be future proof.

[diegomura]

Sgtm! Thanks for the input @blikblum . Done in decd6ba

[devongovett]

I think we might still need the browser field for backward compatibility though, eg for old tools that don't support exports. Otherwise we'll have to release this in a major version.

[diegomura]

Done! I also wanted to remove Buffer usage in favor of Uint8Array (separately) if that sounds good for you guys. I think that should be breaking, but up to you 😄

[diegomura]

Will this need a "browser" path? If I understood node docs correctly node takes precedence over default, but it also mentions community conditions definitions which I guess are supported but not part of the standard

[blikblum]

No. Browser takes the default

[diegomura]

Thanks for the review @blikblum ! when can we expect to have this merged?

[blikblum]

Need one more review