Proper usage with selective polyfilling?

[jquense]

Is there a good, or preferable setup using preset-modules, along with `preset-env' auto polyfilling? Perhaps all the transforms disabled so the polyfills are also included?

[nicolo-ribaudo]

We will move this preset into preset-env soon (either in the next Babel minor release or in the one after), so it will be enough to use @babel/preset-env with the esmodules: true option.

[developit]

Right - I believe even with all transforms enabled right now preset-env would produce polyfill imports since it isn't aware preset-modules is transforming things. I believe the useBuiltIns:entry option should work in tandem, though.

[jquense]

At the moment i've got them working together but have had to manually exclude any transforms in preset-env. On a tangent it'd be nice to have a leaner polyfill option as well, corejs is thorough, maybe too much so :P

[developit]

@jquense I couldn't agree more! :)

FWIW I've found myself using polyfill.io's configurator tool and then grabbing the resulting polyfills (with the ?flags=always parameter) and just inlining that. I tend to conditionally load it using <script nomodule>.

BTW if you have a working exclude list handy I would love to take a peek. It might be worth dropping it in this issue so we can pin it for folks wondering the same as you were.

[jquense]

its luckily as easy as using a regex since the babel plugins are consistently named https://github.com/4Catalyzer/javascript/blob/esm/packages/babel-preset/esm.js#L25

[developit]

oh, brilliant haha. One thing potentially worth trying would be to exclude known false positive inclusions of corejs:

exclude: [
  /transform/,
  'es.map',
  'es.set',
  'es.object.assign'
]

[ba55ie]

We will move this preset into preset-env soon (either in the next Babel minor release or in the one after), so it will be enough to use @babel/preset-env with the esmodules: true option.

Babel 8 is planned to be released in March. Any chance it will be included then? :)

[nicolo-ribaudo]

It will! And in case we release 7.9.0 before 8.0.0, it will be already included in 7.9.0.

You can turn on notifications for babel/babel#11083 😉

[BregtDeLange]

I don't know where to post this, but the Safari 10 polyfill for supporting "nomodule", is this part of this plugin, or do we still need to include that ourselves?