feat(core): allow non-default-export client config file

[Mister-Hope]

do not require export default {} with client config file

useful for:

• users that only want to add this file for plugin customization purpose
• plugins which only need to add some styles or library imports on the client side with this

[coveralls]

Pull Request Test Coverage Report for Build 9211065904

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 41.16%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/core/src/app/prepare/prepareClientConfigs.ts	0	1	0.0%

Totals
Change from base Build 9184528421:	0.0%
Covered Lines:	688
Relevant Lines:	1709

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💛 - Coveralls

[meteorlxy]

1. Better to check default export in node side instead of filtering it in client code.
2. Better to add e2e tests for the changes.

[Mister-Hope]

I'm not pretty sure about the first one, So you mean importing this file on the node side and see if the default export is available?

So what's the motivation of this? We can't just filter those files which does not have sport because we shall import them anyway to have their library and style file imported. Also, if the file is containing some style files import like css and scss, An error is expected at node side because we are not dealing them with bundlers.

And I think there is no actual performance decrease for using a namespace import, Because only the default export is expected on this file.

[meteorlxy]

I mean to check the file content in node side or something. As I remember, v1 did similar thing by checking export default keyword.

It could avoid the extra .map((m) => m.default).filter(Boolean) in client side.

But yes it's nice to have but not such necessary.

[Mister-Hope]

I think checking without ast may introduce fail positive, so I prefer the original one. I don't think ast check should be introduced here.

[Mister-Hope]

A e2e test about config file with no export default is added.

[Mister-Hope]

shit, why is windows failing (ー_ー)!!

[meteorlxy]

Should check if the styles are applied correctly to the target elements