Vite injects __vitePreload even if the modulePreload option is disabled

[lubomirblazekcz]

Describe the bug

Vite injects __vitePreload on each dynamic import, I would expected this not be included when modulePreload is set to false.

Eg. If I want to handle preloading manually or not at all.

Related #13952 #13973

Reproduction

https://stackblitz.com/edit/vitejs-vite-p54vgg

Steps to reproduce

Run vite build and the output is actually larger then the source.

System Info

..

Used Package Manager

npm

Logs

No response

Validations

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[bluwy]

Related: #13973

[vritant24]

In our scenario, preloading any file causes errors as we have a tricky way of resolving file paths (our code runs inside a vscode controlled iframe).
Specifically __vitePreload injects a stylesheet link that causes our page to not load.

Following the referenced PRs and issues, I understand why it's the case, but is there a workaround to prevent the runtime injection of the preloads today?

[lilnasy]

I was also very confused by this and I poured over several documentaion pages, issues, and discussions to determine what I was doing wrong.

If the preload helper is doing more than just helping with preloading module scripts, as #13973, could this be considered a communication issue and be solved as such. For example, by reevaluating how vite names the relevant code.

[wmertens]

Indeed, __vitePreload does two things even when modulePreload: false:

1. inject imported stylesheets for dynamic imports
2. emit vite:preloadError event when preload fails

I think 1) can be detected at build time, and the __vitePreload can be removed if there are no deps, and 2) is not important IMHO, it could be replaced with a generic error handler for all <link> elements

[HonmaMeikodesu]

I quite cant get what modulePreload : false means, for now i have to create a rollup plugin in render phase to completely get rid of the _vitePreload occuring in my dynamic import statements

[lubomirblazekcz]

#19505 (comment)

This seems to work as a workaround