Support of babel 6 and babel 7

[igor-dv]

Hey,

I would like to use this package in Storybook. In my PR here, I've temporarily copied the code in order to make a progress.

The problem is that Sotrybook has a peer of bable-loader in order to allow people still to use babel 6.
That means, we can't be dependant on a package that is directly dependant on @babel/core.
So I've created a babel-core-proxy that does something like this:

/* eslint-disable import/no-extraneous-dependencies,global-require */
let babelCore = null;

try {
  babelCore = require('@babel/core');
} catch (e) {
  babelCore = require('babel-core');
}

module.exports = babelCore;

And then used it in the babel-merge code:

import { resolvePlugin, resolvePreset } from './babel-core-proxy';

Will you consider this change as a pull request ?

The downside of this approach is that babel-core and @babel/core can't be in a list of peerDeps, but it's something that can be documented 🤷‍♂️

Thanks.

[ndelangen]

Hey @neutrinojs we'd really love to use this package over at storybook, do you think if @igor-dv made a PR you'd accept it?

[edmorley]

Hi! Thank you for reaching out :-)

In the Storybook PR, I see references to Babel 7 specific package names, eg:
https://github.com/storybooks/storybook/pull/4027/files#diff-6b922c89c3c27503a2a2eb1dc0112578R5

It seems like even with the proposed changes here, that won't work under Babel 6?

The downside of this approach is that babel-core and @babel/core can't be in a list of peerDeps, but it's something that can be documented 🤷‍♂️

Do you mean deps instead of peerDeps? ie: Users of babel-merge would need to follow the documentation since there will no no dep or peeDep on babel core? If so, perhaps I think there is a way for babel-merge to be able to have a peerDep on babel core - using the bridge package:
https://github.com/babel/babel-bridge

Babel 7 has so many improvements, it seems like encouraging users to upgrade to it would be worth the effort long-term. There's a Babel package for assisting with migration that to which users could be directed?
https://github.com/babel/babel-upgrade

However @eliperelman has more of a stake in the direction of this package than I, so will probably have more thoughts :-)

[edmorley]

Hmm actually thinking about this, I believe that babel-merge should never have had a dependency on @babel/core in the first place - it should always have been in peerDependencies. As such, the bridge package seems like the correct solution.

[igor-dv]

In the Storybook PR, I see references to Babel 7 specific package names, eg:

it's true, but people that still use babel 6, can just use their .babelrc, instead of ours, and it will work for them.

Users of babel-merge would need to follow the documentation since there will no dep or peeDep on babel core

Yeah 😅

babel-core

It's actually a nice idea.

peerDependencies: {
  "babel-core": "6.x || ^7.0.0-bridge.0"
}

Again, there will be a need to install the bridge even if you are using babel@7. Also, we will need to have a peer on "babel-core": "6.x || ^7.0.0-bridge.0" 🤔

[ndelangen]

Sounds awesome @edmorley

[eliperelman]

I'm totally fine going the bridge peerDep route. Worst case scenario, we can backport some of the merge changes from 3.x into 2.x which works on Babel 6.