npm / svelte-preprocess
svelte-preprocess
What changed in svelte-preprocess 5 to 6, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-27.
3 breaking4 fixes and other
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npx @unstale/cli initsvelte-preprocess 62 changes
Fixes and other changes 2
Correctly imports the transformer when automatically processing with TypeScript 6.
Adds support for TypeScript 6.
svelte-preprocess 55 changes
Breaking changes 3
Languages must be explicitly defined via the lang attribute; the type attribute can no longer identify a style or script language.
The minimum Node version is now 14, increased from 9.
node-sass is no longer supported; use sass instead.
Fixes and other changes 2
The .sss extension is mapped as .css to support the SugarSS extension.
SugarSS versions 3 and 4 are supported.