From b791cac54e2db43317f2bc6c8e41e694245c551e Mon Sep 17 00:00:00 2001
From: Manuel <30698007+manuel3108@users.noreply.github.com>
Date: Sat, 18 Jul 2026 14:47:30 +0200
Subject: [PATCH] chore: provide `indent` option for `print` (#18474)

Relevant for https://github.com/sveltejs/cli/pull/1138.
This is basically just an option from `esrap` that we pass through. That
will allow tools like `sv migrate` to provide a guessed indent based on
the other file contents and therefore allow us to produce way smaller
diffs. Since we are just passing an option, there is no need for a test
here.

Technically a `feat:` but i dont think this is relevant enough.

### Before submitting the PR, please make sure you do the following

- [x] 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
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).

### Tests and linting

- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---
 .changeset/short-otters-find.md               | 5 +++++
 packages/svelte/src/compiler/print/index.js   | 5 ++++-
 packages/svelte/src/compiler/print/types.d.ts | 1 +
 packages/svelte/types/index.d.ts              | 1 +
 4 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/short-otters-find.md

diff --git a/.changeset/short-otters-find.md b/.changeset/short-otters-find.md
new file mode 100644
index 0000000000..57194653b6
--- /dev/null
+++ b/.changeset/short-otters-find.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: provide `indent` option for `print`
diff --git a/packages/svelte/src/compiler/print/index.js b/packages/svelte/src/compiler/print/index.js
index fbd7e86f12..a5fbc96fc8 100644
--- a/packages/svelte/src/compiler/print/index.js
+++ b/packages/svelte/src/compiler/print/index.js
@@ -30,7 +30,10 @@ export function print(ast, options = undefined) {
 			}),
 			...svelte_visitors(comments),
 			...css_visitors
-		})
+		}),
+		{
+			indent: options?.indent
+		}
 	);
 }
 
diff --git a/packages/svelte/src/compiler/print/types.d.ts b/packages/svelte/src/compiler/print/types.d.ts
index d0ff909525..9eccebb6f3 100644
--- a/packages/svelte/src/compiler/print/types.d.ts
+++ b/packages/svelte/src/compiler/print/types.d.ts
@@ -4,4 +4,5 @@ import type ts from 'esrap/languages/ts';
 export type Options = {
 	getLeadingComments?: NonNullable<Parameters<typeof ts>[0]>['getLeadingComments'] | undefined;
 	getTrailingComments?: NonNullable<Parameters<typeof ts>[0]>['getTrailingComments'] | undefined;
+	indent?: string; // default tab
 };
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 5f41fabf60..d758022ae4 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -1854,6 +1854,7 @@ declare module 'svelte/compiler' {
 	type Options = {
 		getLeadingComments?: NonNullable<Parameters<typeof ts>[0]>['getLeadingComments'] | undefined;
 		getTrailingComments?: NonNullable<Parameters<typeof ts>[0]>['getTrailingComments'] | undefined;
+		indent?: string; // default tab
 	};
 
 	export {};