[RFC] Drop CommonJS entry point

[susnux]

We currently provide CommonJS and ESM entry points.
While ESM is able to import CommonJS packages, the opposite does only work with dynamic import() and not with require().

This causes issues as some of our dependencies are pure ESM dependencies, meaning our CJS output is theoretically invalid, because it contains require('pure-esm-module').
This causes issues with tools like jest, as the code is not valid.

(Notice that for app users this is not a problem, if they use Vite it will load the ESM entry and if they use webpack it will transpile this library and all dependencies to UMD)

But I see no benefit of providing both types, as CommonJS users will still have to transpile this library because of the dependencies.

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My reasons for going pure ESM:

• Less error prone distribution (we had problems with one of both types being invalid with both webpack and vite)
• ESM is the standard (and hopefully someday being it also in the Node.js universe)
• Simplify tooling & build process
• Smaller distribution size
• Needs to be transpiled anyway so should be no change for users.

I am happy to hear your thoughts, especially if you know reasons for keeping both 😃

[raimund-schluessler]

What is needed to implement this? Just drop main and all the export.*.require fields in package.json?