use syntheticNamedExports

[LarsDenBakker]

• Rollup Plugin Name: commonjs
• Rollup Plugin Version: any

Feature Use Case

Commonjs exports can be very hard to detect. The new syntheticNamedExports feature will be very useful for this. See: rollup/rollup#3295

Feature Proposal

Implement syntheticNamedExports in the commonjs plugin.

If noone is picking this up already, I can take a look at it.

[lukastaegert]

If noone is picking this up already

Not to my knowledge, would be really awesome if you picked this up! You can also add me as a reviewer if you want as I am really interested if the feature actually worked out how it should.

My hope is that as part of this, we can finally deprecated the infamous namedExports option, maybe show a warning message if it is used that it is ignored.

I think it should not be too difficult: Just set the flag for every CJS module and run some tests if it actually works. But if there are issues, feel free to contact me (and possibly @manucorporat who originally implemented the Rollup feature).

[manucorporat]

Please! Give it a try, and ping me if something not working as expected. This will be awesome for CommonJS integration:

• dynamic named exports
• Exports is a proxy
• circular dependencies that add exports

I think we could leave the plugin as it is, so it keeps working in older versions of rollup, then is latest rollup missing exports fallback to the default export.

Or do we want to require the latest rollup version?

[LarsDenBakker]

I played around with this a bit, but it seems something isn't quite correct yet for exported synthetic named exports.

If I take your example, but change:

import {foo, bar, other} from './dep.js'
console.log(foo, bar, other);

to:

export {foo, bar, other} from './dep.js'

the output becomes:

const other = 'thing';
var dep = {
   foo: 42,
   bar: 'hello'
};

export { bar, foo, other };

so the synthetic named exports aren't actually taken from the object.

I put a repro here: https://github.com/LarsDenBakker/rollup-synthetic-named-exports

[manucorporat]

@LarsDenBakker i will take a look today

[LarsDenBakker]

Besides that, I did get a fairly large project with a large variety of commonjs modules built and run with a modified version of the commonjs plugin. So thats great news :)

[shellscape]

@LarsDenBakker would it be worthwhile for us to take a look at your fork?

[manucorporat]

WIP PR to fix this issue:
rollup/rollup#3319

[LarsDenBakker]

@LarsDenBakker would it be worthwhile for us to take a look at your fork?

Of course, I will make it into a PR