From 990916ae7f0d3925418e78c23f497b5d94698409 Mon Sep 17 00:00:00 2001
From: Dunqing <29533304+Dunqing@users.noreply.github.com>
Date: Wed, 22 Oct 2025 07:34:10 +0000
Subject: [PATCH] fix(formatter): correct handling of leading own line before
 arrow function body (#14877)

close: https://github.com/oxc-project/oxc/issues/14871
---
 .../src/write/arrow_function_expression.rs    | 12 ++++------
 .../tests/fixtures/js/comments/arrow.js       |  7 ++++++
 .../tests/fixtures/js/comments/arrow.js.snap  | 22 +++++++++++++++++++
 3 files changed, 33 insertions(+), 8 deletions(-)
 create mode 100644 crates/oxc_formatter/tests/fixtures/js/comments/arrow.js
 create mode 100644 crates/oxc_formatter/tests/fixtures/js/comments/arrow.js.snap

diff --git a/crates/oxc_formatter/src/write/arrow_function_expression.rs b/crates/oxc_formatter/src/write/arrow_function_expression.rs
index e76a840e88666..7bf5dc8339b3e 100644
--- a/crates/oxc_formatter/src/write/arrow_function_expression.rs
+++ b/crates/oxc_formatter/src/write/arrow_function_expression.rs
@@ -159,22 +159,18 @@ impl<'a> Format<'a> for FormatJsArrowFunctionExpression<'a, '_> {
                     };
                 }
 
-                #[expect(clippy::match_same_arms)]
-                let body_has_soft_line_break = arrow_expression.is_none_or(|expression| {
-                    match expression {
+                let body_has_soft_line_break =
+                    arrow_expression.is_none_or(|expression| match expression {
                         Expression::ArrowFunctionExpression(_)
                         | Expression::ArrayExpression(_)
                         | Expression::ObjectExpression(_) => {
-                            // TODO: It seems no difference whether check there is a leading comment or not.
-                            // !f.comments().has_leading_own_line_comment(body.span().start)
-                            true
+                            !f.comments().has_leading_own_line_comment(body.span().start)
                         }
                         Expression::JSXElement(_) | Expression::JSXFragment(_) => true,
                         _ => {
                             is_multiline_template_starting_on_same_line(expression, f.source_text())
                         }
-                    }
-                });
+                    });
 
                 let body_is_condition_type =
                     matches!(arrow_expression, Some(Expression::ConditionalExpression(_)));
diff --git a/crates/oxc_formatter/tests/fixtures/js/comments/arrow.js b/crates/oxc_formatter/tests/fixtures/js/comments/arrow.js
new file mode 100644
index 0000000000000..9bc75b8521601
--- /dev/null
+++ b/crates/oxc_formatter/tests/fixtures/js/comments/arrow.js
@@ -0,0 +1,7 @@
+() =>
+  // comment
+  [];
+
+() =>
+  // comment
+  ({})
diff --git a/crates/oxc_formatter/tests/fixtures/js/comments/arrow.js.snap b/crates/oxc_formatter/tests/fixtures/js/comments/arrow.js.snap
new file mode 100644
index 0000000000000..d3afaa4201b23
--- /dev/null
+++ b/crates/oxc_formatter/tests/fixtures/js/comments/arrow.js.snap
@@ -0,0 +1,22 @@
+---
+source: crates/oxc_formatter/tests/fixtures/mod.rs
+---
+==================== Input ====================
+() =>
+  // comment
+  [];
+
+() =>
+  // comment
+  ({})
+
+==================== Output ====================
+() =>
+  // comment
+  [];
+
+() =>
+  // comment
+  ({});
+
+===================== End =====================