fix(js_formatter): placements of line comments between function parentheses and body

CHANGELOG.md

@@ -20,6 +20,10 @@ Read our [guidelines for writing a good changelog entry](https://github.com/biom
 
 ### Formatter
 
+#### Bug fixes
+
+- Fix [#1172](https://github.com/biomejs/biome/issues/1172). Fix placement of line comment after function expression parentheses, they are now attached to first statement in body. Contributed by @kalleep
+
 ### JavaScript APIs
 
 ### Linter

crates/biome_js_formatter/src/comments.rs

@@ -100,7 +100,7 @@ impl CommentStyle for JsCommentStyle {
     ) -> CommentPlacement<Self::Language> {
         match comment.text_position() {
             CommentTextPosition::EndOfLine => handle_typecast_comment(comment)
-                .or_else(handle_function_declaration_comment)
+                .or_else(handle_function_comment)
                 .or_else(handle_conditional_comment)
                 .or_else(handle_if_statement_comment)
                 .or_else(handle_while_comment)
@@ -119,7 +119,7 @@ impl CommentStyle for JsCommentStyle {
                 .or_else(handle_after_arrow_fat_arrow_comment)
                 .or_else(handle_import_export_specifier_comment),
             CommentTextPosition::OwnLine => handle_member_expression_comment(comment)
-                .or_else(handle_function_declaration_comment)
+                .or_else(handle_function_comment)
                 .or_else(handle_if_statement_comment)
                 .or_else(handle_while_comment)
                 .or_else(handle_try_comment)
@@ -641,38 +641,32 @@ fn handle_member_expression_comment(
     }
 }
 
-fn handle_function_declaration_comment(
-    comment: DecoratedComment<JsLanguage>,
-) -> CommentPlacement<JsLanguage> {
-    let is_function_declaration = matches!(
+fn handle_function_comment(comment: DecoratedComment<JsLanguage>) -> CommentPlacement<JsLanguage> {
+    if !matches!(
         comment.enclosing_node().kind(),
         JsSyntaxKind::JS_FUNCTION_DECLARATION
             | JsSyntaxKind::JS_FUNCTION_EXPORT_DEFAULT_DECLARATION
-    );
+            | JsSyntaxKind::JS_FUNCTION_EXPRESSION
+    ) || !comment.kind().is_line()
+    {
+        return CommentPlacement::Default(comment);
+    };
 
-    let following = match comment.following_node() {
-        Some(following) if is_function_declaration => following,
-        _ => return CommentPlacement::Default(comment),
+    let Some(body) = comment.following_node().and_then(JsFunctionBody::cast_ref) else {
+        return CommentPlacement::Default(comment);
     };
 
-    // Make comments between the `)` token and the function body leading comments
-    // of the first non empty statement or dangling comments of the body.
+    // Make line comments between the `)` token and the function body leading comments
+    // of the first statement or dangling comments of the body.
     // ```javascript
-    // function test() /* comment */ {
+    // function test() // comment
+    // {
     //  console.log("Hy");
     // }
     // ```
-    if let Some(body) = JsFunctionBody::cast_ref(following) {
-        match body
-            .statements()
-            .iter()
-            .find(|statement| !matches!(statement, AnyJsStatement::JsEmptyStatement(_)))
-        {
-            Some(first) => CommentPlacement::leading(first.into_syntax(), comment),
-            None => CommentPlacement::dangling(body.into_syntax(), comment),
-        }
-    } else {
-        CommentPlacement::Default(comment)
+    match body.statements().first() {
+        Some(first) => CommentPlacement::leading(first.into_syntax(), comment),
+        None => CommentPlacement::dangling(body.into_syntax(), comment),
     }
 }
 

crates/biome_js_formatter/tests/specs/js/module/function/function_comments.js

@@ -11,7 +11,29 @@ function b() // leading comment
 
 }
 
-
 function c( //some comment
     foo, bar,
-) {}
+) {}
+
+
+(function d()
+// a
+{
+  return 42
+});
+
+function e()
+// a
+{
+  ;
+};
+
+function f()
+// a
+{
+  a;
+};
+
+function h() /* a */ {
+	a;
+};

crates/biome_js_formatter/tests/specs/js/module/function/function_comments.js.snap

@@ -19,10 +19,33 @@ function b() // leading comment
 
 }
 
-
 function c( //some comment
     foo, bar,
 ) {}
+
+
+(function d()
+// a
+{
+  return 42
+});
+
+function e()
+// a
+{
+  ;
+};
+
+function f()
+// a
+{
+  a;
+};
+
+function h() /* a */ {
+	a;
+};
+
 ```
 
 
@@ -65,6 +88,24 @@ function c(
 	foo,
 	bar,
 ) {}
+
+(function d() {
+	// a
+	return 42;
+});
+
+function e() {
+	// a
+}
+
+function f() {
+	// a
+	a;
+}
+
+function h() /* a */ {
+	a;
+}
 ```
 
 

crates/biome_js_formatter/tests/specs/prettier/js/comments/function/between-parentheses-and-function-body.js

@@ -4,22 +4,18 @@ function function_declaration()
   return 42
 }
 
-// FIXME
-// TODO: reformat issue
-// (function named()
-// // this is a function
-// {
-//   return 42
-// })();
+(function named()
+// this is a function
+{
+  return 42
+})();
 
 
-// FIXME
-// TODO: reformat issue
-// (function ()
-// // this is a function
-// {
-//   return 42
-// })();
+(function ()
+// this is a function
+{
+  return 42
+})();
 
 /* anonymous declaration */
 export default function ()
@@ -28,14 +24,12 @@ export default function ()
   return 42
 }
 
-// FIXME
-// TODO: reformat issue
 a = {
   foo()
   // this is a function
   {},
 
-// bar: function()
-// // this is a function
-// {},
+  bar: function()
+  // this is a function
+  {},
 }

website/src/content/docs/internals/changelog.mdx

@@ -26,6 +26,10 @@ Read our [guidelines for writing a good changelog entry](https://github.com/biom
 
 ### Formatter
 
+#### Bug fixes
+
+- Fix [#1172](https://github.com/biomejs/biome/issues/1172). Fix placement of line comment after function expression parentheses, they are now attached to first statement in body. Contributed by @kalleep
+
 ### JavaScript APIs
 
 ### Linter