perf: shorten file names

[benmccann]

This shortens references to JS files in SSR, JS, and HTTP headers. Less bytes referring to these files. Also, the chunks often pick combine multiple files and pick the name of one individual file to use for the chunk, which can be misleading

Reducing the size of asset names reduced the size of the JS on my image-heavy page by 6.5% after brotli compression, but we couldn't come to agreement to shorten those

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🦋 Changeset detected

Latest commit: 2e91dab

The changes in this PR will be included in the next version bump.

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@sveltejs/kit	Patch

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[Rich-Harris]

preview: https://svelte-dev-git-preview-kit-13003-svelte.vercel.app/

this is an automated message

[dominikg]

this could be a breaking change.it's going to bust existing users caches due to the change in output names, and if they used those somewhere without resolution through manifest, those references break too.

[benmccann]

it's going to bust existing users caches due to the change in output names

it wouldn't be the first time we've changed it and no one's ever complained before. static assets are incredibly cheap to serve

if they used those somewhere without resolution through manifest, those references break too

the filenames already change everytime a single character changes and I don't know what you can do referencing an individual file anyway

[dominikg]

assets don't change that often. this will force all users to download everything again they already had far future cached. images, fonts, everything...

how often did we change it? if we offer immutable asset caching as a feature, we should be mindful not to bust that

[benmccann]

Yeah, we've changed it very rarely

[dummdidumm]

How useful are/were the names before? I remember debugging stuff and it was helpful to have the names there.

[Rich-Harris]

It varies. Asset filenames are very useful, and after discussion this PR keeps them unchanged. Entry filenames are useful and they're also unchanged. Chunk filenames are often actively misleading because they're essentially random. I haven't double-checked that routes are considered entries rather than chunks — I think they are — as long as that's true then I'm in favour of this change

[dummdidumm]

I just checked, and yes route names are preserved (i.e. it's 0.hash-123, 1.hash-123 etc), so I'm guessing all other relevant entries will also preserved.
You're right that other chunk names can be misleading because there could be other stuff in there aswell.