From 638a0dbb1acd239ad9d5f3fd8c95f017cc5ad5f1 Mon Sep 17 00:00:00 2001
From: Dunqing <dengqing0821@gmail.com>
Date: Wed, 20 Nov 2024 00:23:22 +0800
Subject: [PATCH] add should_create_temp_variable_for_identifier

---
 .../src/es2020/optional_chaining.rs           | 38 ++++++++++++-------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/crates/oxc_transformer/src/es2020/optional_chaining.rs b/crates/oxc_transformer/src/es2020/optional_chaining.rs
index 6e2880de0aa19..38d6c065988f3 100644
--- a/crates/oxc_transformer/src/es2020/optional_chaining.rs
+++ b/crates/oxc_transformer/src/es2020/optional_chaining.rs
@@ -134,6 +134,16 @@ impl<'a, 'ctx> OptionalChaining<'a, 'ctx> {
         }
     }
 
+    /// Check if we should create a temp variable for the identifier
+    ///
+    /// Except the `eval`, we should create a temp variable for all global references
+    fn should_create_temp_variable_for_identifier(
+        ident: &IdentifierReference<'a>,
+        ctx: &TraverseCtx<'a>,
+    ) -> bool {
+        ident.is_global_reference(ctx.symbols()) && ident.name != "eval"
+    }
+
     /// Skip transparent expression wrapper nodes
     fn skip_transparent_expr_wrapper_nodes<'b>(
         ctx: &'b TraverseCtx<'a>,
@@ -422,6 +432,7 @@ impl<'a, 'ctx> OptionalChaining<'a, 'ctx> {
         let expr = expr.get_inner_expression_mut();
         // (nest member expressions have transformed, current optional expr that need to transform)
         match expr {
+            // nested chain expression like `(foo?.bar)?.baz`
             Expression::ChainExpression(_) => {
                 *expr = Self::convert_chain_expression_to_expression(expr, ctx);
                 let left = self.transform_chain_expression_recursion(expr, ctx).unwrap();
@@ -511,7 +522,7 @@ impl<'a, 'ctx> OptionalChaining<'a, 'ctx> {
         // If the expression is an identifier and it's not a global reference, we just to wrap it with checks
         // `foo` -> `foo !== null && foo !== void 0`
         if let Expression::Identifier(ident) = expr {
-            if !ident.is_global_reference(ctx.symbols()) || ident.name == "eval" {
+            if !Self::should_create_temp_variable_for_identifier(ident, ctx) {
                 let binding = MaybeBoundIdentifier::from_identifier_reference(ident, ctx);
                 let left1 = binding.create_read_expression(ctx);
                 let left2 = binding.create_read_expression(ctx);
@@ -527,19 +538,18 @@ impl<'a, 'ctx> OptionalChaining<'a, 'ctx> {
                 // If the [`MemberExpression::object`] is a global reference, we need to assign it to a temp binding.
                 // i.e `foo` -> `(_foo = foo)
                 if let Expression::Identifier(ident) = object {
-                    let binding =
-                        if ident.is_global_reference(ctx.symbols()) && ident.name != "eval" {
-                            let binding = self.generate_binding(object, ctx);
-                            // `(_foo = foo)`
-                            *object = Self::create_assignment_expression(
-                                binding.create_read_write_target(ctx),
-                                ctx.ast.move_expression(object),
-                                ctx,
-                            );
-                            binding.to_maybe_bound_identifier()
-                        } else {
-                            MaybeBoundIdentifier::from_identifier_reference(ident, ctx)
-                        };
+                    let binding = if Self::should_create_temp_variable_for_identifier(ident, ctx) {
+                        let binding = self.generate_binding(object, ctx);
+                        // `(_foo = foo)`
+                        *object = Self::create_assignment_expression(
+                            binding.create_read_write_target(ctx),
+                            ctx.ast.move_expression(object),
+                            ctx,
+                        );
+                        binding.to_maybe_bound_identifier()
+                    } else {
+                        MaybeBoundIdentifier::from_identifier_reference(ident, ctx)
+                    };
                     self.set_binding_context(binding);
                 } else if matches!(object, Expression::Super(_)) {
                     self.set_this_context();