fix(formatter): block comments without a trailing linebreak that come after the ? operator in a conditional expression should be printed as-is

Author: Dunqing

crates/oxc_formatter/src/utils/conditional.rs

@@ -144,13 +144,13 @@ fn format_trailing_comments<'a>(
             if source_text.contains_newline_between(start, comment.span.start) {
                 return &comments[..index];
             }
-            // If this comment is a line comment, then it is a end of line comment, so we stop here and return the comments with this comment
-            else if comment.is_line() {
+            // If this comment is a line comment or an end of line comment, so we stop here and return the comments with this comment
+            else if comment.is_line() || source_text.is_end_of_line_comment(comment) {
                 return &comments[..=index];
             }
             // Store the index of the comment before the operator, if no line comment or no new line is found, then return all comments before operator
             else if source_text.bytes_contain(start, comment.span.start, operator) {
-                index_before_operator = Some(index + 1);
+                index_before_operator = Some(index);
             }
 
             // Update the start position for the next iteration
@@ -161,9 +161,7 @@ fn format_trailing_comments<'a>(
     };
 
     let comments = get_comments(f);
-    FormatTrailingComments::Comments(comments).fmt(f)?;
-
-    Ok(())
+    FormatTrailingComments::Comments(comments).fmt(f)
 }
 
 impl<'a> FormatConditionalLike<'a, '_> {

crates/oxc_formatter/tests/fixtures/js/comments/conditional.js

@@ -0,0 +1,5 @@
+test /* comment1 */ ? /* comment2 */ consequent /* comment3 */ : /* comment4 */ alternative
+
+test 
+/* comment1 */ ? /* comment2 */ consequent 
+/* comment3 */ : /* comment4 */ alternative

crates/oxc_formatter/tests/fixtures/js/comments/conditional.js.snap

@@ -0,0 +1,20 @@
+---
+source: crates/oxc_formatter/tests/fixtures/mod.rs
+---
+==================== Input ====================
+test /* comment1 */ ? /* comment2 */ consequent /* comment3 */ : /* comment4 */ alternative
+
+test 
+/* comment1 */ ? /* comment2 */ consequent 
+/* comment3 */ : /* comment4 */ alternative
+
+==================== Output ====================
+test /* comment1 */
+  ? /* comment2 */ consequent /* comment3 */
+  : /* comment4 */ alternative;
+
+test
+  ? /* comment1 */ /* comment2 */ consequent
+  : /* comment3 */ /* comment4 */ alternative;
+
+===================== End =====================