From 18fa8e45a4f254a5ce1b0886cdda22afdabf56df Mon Sep 17 00:00:00 2001
From: Boshen <boshenc@gmail.com>
Date: Sun, 19 Nov 2023 17:48:09 +0800
Subject: [PATCH] feat(prettier): format `for((let) of ..` (#1429)

---
 crates/oxc_prettier/src/format/mod.rs       | 40 ++++++++++++++++++++-
 tasks/prettier_conformance/prettier.snap.md |  6 +---
 2 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/crates/oxc_prettier/src/format/mod.rs b/crates/oxc_prettier/src/format/mod.rs
index f7ed65f60..8c55dce39 100644
--- a/crates/oxc_prettier/src/format/mod.rs
+++ b/crates/oxc_prettier/src/format/mod.rs
@@ -243,7 +243,45 @@ impl<'a> Format<'a> for ForOfStatement<'a> {
                 parts.push(ss!(" await"));
             }
             parts.push(ss!(" ("));
-            parts.push(format!(p, self.left));
+
+            // for ((async) of []);
+            // for ((let) of []);
+            // for ((let.a) of []);
+            let mut should_hug = false;
+            if let ForStatementLeft::AssignmentTarget(AssignmentTarget::SimpleAssignmentTarget(
+                target,
+            )) = &self.left
+            {
+                if let SimpleAssignmentTarget::AssignmentTargetIdentifier(ident) = target {
+                    if ident.name == "let" {
+                        should_hug = true;
+                    }
+                    if ident.name == "async" && !self.r#await {
+                        should_hug = true;
+                    }
+                }
+                if let SimpleAssignmentTarget::MemberAssignmentTarget(member_expr) = target {
+                    let object = match &**member_expr {
+                        MemberExpression::ComputedMemberExpression(e) => Some(&e.object),
+                        MemberExpression::StaticMemberExpression(e) => Some(&e.object),
+                        MemberExpression::PrivateFieldExpression(e) => None,
+                    };
+                    if let Some(Expression::Identifier(ident)) = object {
+                        if ident.name == "let" {
+                            should_hug = true;
+                        }
+                    }
+                }
+            }
+
+            if should_hug {
+                parts.push(ss!("("));
+                parts.push(format!(p, self.left));
+                parts.push(ss!(")"));
+            } else {
+                parts.push(format!(p, self.left));
+            }
+
             parts.push(ss!(" of "));
             parts.push(format!(p, self.right));
             parts.push(ss!(")"));
diff --git a/tasks/prettier_conformance/prettier.snap.md b/tasks/prettier_conformance/prettier.snap.md
index c4b29535e..8fd70a50a 100644
--- a/tasks/prettier_conformance/prettier.snap.md
+++ b/tasks/prettier_conformance/prettier.snap.md
@@ -1,4 +1,4 @@
-Compatibility: 119/838 (14.20%)
+Compatibility: 121/838 (14.44%)
 
 # Failed
 
@@ -476,9 +476,6 @@ Compatibility: 119/838 (14.20%)
 ### for-await
 * for-await/for-await.js
 
-### for-of
-* for-of/async-identifier.js
-
 ### function
 * function/function_expression.js
 * function/issue-10277.js
@@ -514,7 +511,6 @@ Compatibility: 119/838 (14.20%)
 * generator/function-name-starts-with-get.js
 
 ### identifier/for-of
-* identifier/for-of/await.js
 * identifier/for-of/let.js
 
 ### identifier/parentheses