From 85ac3f749aa663bc8c79b4773fdc2bbfabf2cf14 Mon Sep 17 00:00:00 2001
From: overlookmotel <557937+overlookmotel@users.noreply.github.com>
Date: Tue, 17 Sep 2024 14:11:05 +0000
Subject: [PATCH] refactor(transformer): arrow functions transform do not wrap
 function expressions in parentheses (#5824)

Wrapping a function expression in parentheses is unnecessary. Codegen already adds parentheses when printing a function expression as a statement expression. i.e. `(function() {});`.
---
 crates/oxc_transformer/src/es2015/arrow_functions.rs | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/crates/oxc_transformer/src/es2015/arrow_functions.rs b/crates/oxc_transformer/src/es2015/arrow_functions.rs
index 5dc2b055a..0fa8e6901 100644
--- a/crates/oxc_transformer/src/es2015/arrow_functions.rs
+++ b/crates/oxc_transformer/src/es2015/arrow_functions.rs
@@ -112,12 +112,12 @@ impl<'a> Traverse<'a> for ArrowFunctions<'a> {
 
     /// ```ts
     /// function a(){
-    ///    () => console.log(this);
+    ///   return () => console.log(this);
     /// }
     /// // to
     /// function a(){
     ///   var _this = this;
-    ///  (function() { return console.log(_this); });
+    ///   return function() { return console.log(_this); };
     /// }
     /// ```
     /// Insert the var _this = this; statement outside the arrow function
@@ -306,10 +306,7 @@ impl<'a> ArrowFunctions<'a> {
         );
         new_function.scope_id.set(scope_id);
 
-        let expr = Expression::FunctionExpression(self.ctx.ast.alloc(new_function));
-        // Avoid creating a function declaration.
-        // `() => {};` => `(function () {});`
-        self.ctx.ast.expression_parenthesized(SPAN, expr)
+        Expression::FunctionExpression(self.ctx.ast.alloc(new_function))
     }
 
     /// Insert `var _this = this;` at the top of the statements.