fix(vite): conditional exports can't be active when key is browser (#18012)

[NWYLZW]

Description

#18012 (comment)

Based on my debugging results, the handling here seems a bit too tightly coupled with SSR. For other users encountering this issue, you can try setting the ssrTarget parameter to 'webworker'. However, I believe this area should take into account that the user has already actively declared the conditional.

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[sapphi-red]

@NWYLZW Would you elaborate your usecase? Are you testing a library using Vitest for browser on Node without any shims like JSDOM?

I think this is related to #9860.
@sheremet-va Do you have any thoughts about this?

[NWYLZW]

@NWYLZW Would you elaborate your usecase? Are you testing a library using Vitest for browser on Node without any shims like JSDOM?

I don't need JSDOM here. On the other hand, I feel that using the ssr.target parameter to indirectly influence this is a bit strange. This configuration feels a bit messy; we should respect the user's configuration regarding export conditions.

I think this is related to #9860.

The scenario is somewhat similar to what was mentioned in #9860, but the way it is handled causes node to be activated even when I set the conditional for browser. My export has two implementations based on Node.js and the browser, which leads to the problem.

[NWYLZW]

Hey, I noticed that the current resolve function has switched to using the options.webCompatible check, and this seems to have a significant impact.

I still firmly believe that if a user explicitly declares the corresponding conditional, we should respect their configuration. They shouldn't have to configure another option for this to work. If needed, I can also add related unit tests.

[NWYLZW]

There are some issues with the unit tests, but it seems that I did not introduce them.