feat(pluginutils): add native node es modules support

[TrySound]

Rollup Plugin Name: pluginutils

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

If yes, then include "BREAKING CHANGES:" in the first commit message body, followed by a description of what is breaking.

List any relevant issue numbers:

• default export of plugin-node-resolve does not work when using untranspiled (*.mjs) rollup config #412
• feat(node-resolve): add native node es modules support #413

Description

Enable native node es modules via "exports" field in package.json.
Added custom plugin to generate nested package.json with {"type": "module"}
as an alternative to mjs extension usage. This works similar to rollup distribution.
https://unpkg.com/browse/rollup@2.10.9/dist/es/

This change is necessary before migrating all other plugins.

[shellscape]

let's export this output plugin from https://github.com/rollup/plugins/blob/master/shared/rollup.config.js so we can reuse it

[TrySound]

Looks like there is a blocker
Rich-Harris/estree-walker#23

[TrySound]

@shellscape Bundling estree-walker would eliminate the problem. What do you think?

[shellscape]

@TrySound it's got a pretty small bundle footprint of 2.9kb raw. That should be fine.

[shellscape]

question about the choice to nest these within a directory: our prior file format was index.[format].[extension] for output files. e.g. index.es.js. what's the reasoning behind the choice to put them into directories?

[TrySound]

es/package.json with {type:module}

[TrySound]

As an alternative to .mjs extension.

[shellscape]

OK. Can you explain in the PR description why we need mjs alternative? I've added a bunch more people to review. We're going to need to get majority buy-in to move forward with this since it's a pretty big paradigm shift.

[danielgindi]

@TrySound can you please explain why we need to shift from mjs?

[TrySound]

I just don't like it. And to be consistent with rollup. So no strong opinion.

[shellscape]

And to be consistent with Rollup

That seems the most compelling reason. I really don't like how it litters dist but if that stops the complaining about Node 14+ imports then I guess that's what we do.

If we're going to adopt this, we should also revisit comments by @Andarist where dist files were named pluginutils.js instead of index.js, as that would also follow parent Rollup's convention.

[shellscape]

I'll be following up with a PR to address the comment from above:

If we're going to adopt this, we should also revisit comments by @Andarist where dist files were named pluginutils.js instead of index.js, as that would also follow parent Rollup's convention.