docs: link tsconfig sections to kit config

[theetrain]

Sometimes folks may not be aware that changes to top-level tsconfig.json configs such as include will override instead of merge with the generated .svelte-kit/tsconfig.json via extends.

This PR links to the typscript config option in svelte.config.js next to other relevant sections to help boost awareness.

(no related ticket)

---

Please don't delete this checklist! Before submitting the PR, please make sure you do the following:

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests

• Run the tests with pnpm test and lint the project with pnpm lint and pnpm check

Changesets

• If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running pnpm changeset and following the prompts. Changesets that add features should be minor and those that fix bugs should be patch. Please prefix changeset messages with feat:, fix:, or chore:.

Edits

• Please ensure that 'Allow edits from maintainers' is checked. PRs without this option may be closed.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 5d9118a

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-kit-14026-svelte.vercel.app/

[benmccann]

This is great! Thank you!

If you're up for it, I think it'd also be helpful to include an example in /docs/kit/configuration#typescript

[eltigerchino]

Thank you! I didn't even know this was a thing until now. Do you know if the paths passed through this setting should be relative to the location of the generated tsconfig? (I think having the example Ben mentioned would help here)

An out-of-scope random thought: wonder if it's worth typing the typescript.config setting so that it's not just Record<string, any>. Does typescript have a type for the tsconfig?

[Rich-Harris]

thank you!

[Rich-Harris]

Do you know if the paths passed through this setting should be relative to the location of the generated tsconfig?

ooh good point, lemme push a tweak

[Rich-Harris]

I accidentally pushed 9c9bb7e direct to main 🤦 Never mind, it'll have the intended effect

Does typescript have a type for the tsconfig?

I don't think so — the utilities for dealing with config files that TypeScript exports use any, bafflingly