Basic CRA preset does not work on clean project about presets

[mrmckeb]

I've found the issue here and will push it shortly.

[mrmckeb]

@n8sabes, this was caused by the CRA preset applying the wrong loader to files imported by Storybook.

The correction is here:
https://github.com/storybookjs/presets/pull/77/files#diff-80b3f28ef184f3c7a4ac83b1974c3dc6R147

[mrmckeb]

@ljharb you're right - but this was never meant to be transpiled. The loader was simply omitted from the original preset, the new preset was forked from that, and the bug was carried over.

This is the related code:
https://github.com/SeedJobs/react-scripts/blob/master/packages/react-scripts/config/webpack.config.js#L489

[shilman]

What I did:

cra	sb	result
3.3.0	[email protected]	O
3.3.0	[email protected] + [email protected]	X
3.3.0	[email protected] (auto-installs preset-cra)	X
3.3.0	[email protected] - [email protected]	O
3.3.0	[email protected] + [email protected]	X

In other words, the problem appears to be an incompatibility between @storybook/preset-create-react-app and something else in the ecosystem (latest version of CRA? some change in inspect-js (see also: inspect-js/is-map#3)?

Other comments suggest that babel-loader is being applied to node_modules (see inspect-js/is-map#3 (comment))

[pocka]

It seems that this rule tries to transpile is-map and fails?

https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/config/webpack.config.js#L455

[shilman]

Fixed in @storybook/[email protected]!! Please upgrade and try it out! Thanks @mrmckeb for the fix 🙌

[colingm]

Upgrading takes care of it, thank you so much for the quick turn around everyone!

[n8sabes]

@mrmckeb and @shilman -- What was the cause and solution of this issue? I am running into the same problem with another (more mature) CRA project. Downgrading deep-equal to 1.1.1 works around the problem but unsure of the true origin or "correct" fix. Any insight is appreciated.

Please see:
deep-equal issue #78

[ljharb]

Top-level return is perfectly valid inside node modules; transpiling code you didn't author is unsafe; if you're going to transpile node_modules, then you should be sure to use settings that work on valid node modules :-)