fix(worker): non module worker in production

[mathe42]

Description

fixes #4586

In production to do the iife build is so the worker can run in all browsers. But this only works if the worker is then not createt as a module.

Additional context

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
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[mathe42]

This dosn't fix anything. I think it is best practice to change it (as for example chrome fails when useing type: 'worker' for serviceWorker wich is not supported not shure if other browsers also have a early error when type: 'worker' is not supported.

But feel free to close this PR if not needed.

(Note: sometimes you need a non chromium browser to check how different code fails)

[Monkatraz]

No, this PR does fix an obvious bug. Workers are fully bundled under IIFE, but still have { type: "module" } in production, which is pointless.

[mathe42]

Note that Firefox ignores the type option so setting it is ignored.

[Pinpickle]

I'll chime in and say this does fix a bug in certain versions of Chrome where module workers were still experimental and behind a flag. It sees the { type: 'module' } argument and throws an error, prompting the reader to enable module workers in a flag (even though the worker script itself doesn't use modules).

I don't have the error report handy, but I think it might have been Chrome version 74 in the wild.

[mathe42]

Yes agreed this should be Changes!

[Pinpickle]

Is there anything blocking this from getting merged? I'm getting crash reports of workers failing because of this. Tagging @Shinigami92 as I see you added a label to this PR.

The specific error is Failed to construct 'Worker': Module scripts are not supported on DedicatedWorker yet. You can try the feature with '--enable-experimental-web-platform-features' flag (see https://crbug.com/680046) which I've seen reported on versions of Chrome version 79 and under.

[sapphi-red]

Closing as it is currently able to use classic workers.
https://vitejs.dev/guide/features.html#import-with-constructors
https://vitejs.dev/config/#worker-options