Clear and concise description of the problem

For Vite 3, we can review some experimental options to be stable APIs.

Suggested solution

Things to review:

• server.preTransformRequests (feat: option to disable pre-transform #6309)
• server.fs.deny (feat: server.fs.deny support #5378)
• preview() to create a preview server (feat: expose preview method #5014)
• ssrTransform() (feat: expose ssrTransform to server #5983)

Newer experimental options:

• css.devSourcemap (feat(css): css.devSourcemap option #7471)
• optimizeDeps.extensions (feat: optimize custom extensions #6801)

Alternative

No response

Additional context

Note:

For preview(), SvelteKit hasn't been using it as otherwise mentioned in the PR. They work differently that SvelteKit implements its own preview server.

Validations

• Follow our Code of Conduct
• 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.