Improve error message for worker format errors

[PythonCoderAS]

Description

If using code splitting, vite does not allow using 'iife' for workers. However, googling the message directs me to the wrong place for fixing it.

The error message is:

error during build:
[vite:worker] Invalid value "iife" for option "output.format" - UMD and IIFE output formats are not supported for code-splitting builds.

However, googling this will mention build.rollupOptions.output.format, which is not the offending value. Rather, I need to set build.worker.format, but the error message does not mention worker.format in any form.

Suggested solution

The error message should say

[vite:worker] Invalid value "iife" for option "worker.format" - IIFE output format is not supported for code-splitting builds.

Alternative

We can leave it as is and maybe include an entry in the documentation about worker.format.

Additional context

No response

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[7086cmd]

It should be a error throwed by Rollup. I have improved the report message in Rolldown btw.

[avarayr]

Stumbling upon this issue after 1.5 hours of Googling and leading to the wrong path. I appreciate you!

In my case i was getting error

ERROR  [vite-plugin-pwa:build] Invalid value "iife" for option "output.format" - UMD and IIFE output formats are not supported for code-splitting builds.

I'm using vite-plugin-pwa and using web workers using ?worker import.
Fix:

// vite.config.ts
worker: {
      format: "es",
},

Or, if using Vinxi

plugins: () => [
        config("custom", {
          worker: {
            format: "es",
          },
        }),