fix: preact compat

[Grafikart]

With the realease of the version 10 of preact, preact compat was migrated inside preact library removing the need for preact-compat.

https://preactjs.com/guide/v10/switching-to-preact/

[weaverryan]

Thanks for this @Grafikart! One test is failing, with an easy failure.

But I'm a little concerned: this would mean now that Encore only works with preact 10, correct? If so, then we need to update the devDependency for Preact to version 10 - the tests are currently using version 8. And that makes me wonder something else: if you've updated the code for preact 10, but the tests are using version 8, why aren't more significant tests failing? It makes me wonder if the preact functional test - which builds this directory https://github.com/symfony/webpack-encore/tree/master/fixtures/preact - is not "good enough". In theory, that test should be failing right now because of your patch but because the tests are still using Preact 8 right?

Cheers!

[Lyrkan]

if you've updated the code for preact 10, but the tests are using version 8, why aren't more significant tests failing?

I don't think we've functional tests using preact-compat (which is a compatibility layer to use "real" React libraries from your preact app), the one you linked directly uses preact. I guess we could add some but it could be a bit tricky to know they are working properly since we also have react/react-dom in our dev dependencies.

I agree that we should bump the version in our dev dependencies though: if we don't people will be asked to install v8 and then get the wrong aliases for preact-compat if they enable that feature.

[Grafikart]

this would mean now that Encore only works with preact 10, correct?

You are correct. I want input on how you want to handle this situation. We could parse the user package.json (hard way) or we could add a new option within enablePreactPreset.

enablePreactPreset({preactCompat: 10})

In my opinion the build should target the currentVersion. If someone chooses to work with an older version he can setup the aliases manually.

[weaverryan]

I would say that we should either:

A) Only allow version 10 (I have no idea if 8 & 9 have LTS or something like that - I'm not familiar with preact)

B) Allow 8 or 10 and check their installed version to choose which alias to add. We do something similar for Vue 3 in #746. In that, we also have an option to force v2 or v3, but I did that mostly because v2 will be around for an LTS for a long time and because Vue is such a widely-used library.

Btw, my preference would be to only support 10. But if, for some reason, many people will continue to use 8 for a long time, then we could allow both.

[weaverryan]

Thank you @Grafikart!