From aacab9b62b0a4a0e5e7c347a31d93f640aa27811 Mon Sep 17 00:00:00 2001
From: Boshen <boshenc@gmail.com>
Date: Tue, 29 Oct 2024 22:24:04 +0800
Subject: [PATCH] wip

---
 crates/oxc_transformer/src/es2018/mod.rs      | 10 ++++
 .../src/es2018/object_rest_spread.rs          | 60 ++++++++++++++++++-
 crates/oxc_transformer/src/lib.rs             |  8 +++
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/crates/oxc_transformer/src/es2018/mod.rs b/crates/oxc_transformer/src/es2018/mod.rs
index a459d22a3fcd20..66d1d6c25a928e 100644
--- a/crates/oxc_transformer/src/es2018/mod.rs
+++ b/crates/oxc_transformer/src/es2018/mod.rs
@@ -34,4 +34,14 @@ impl<'a, 'ctx> Traverse<'a> for ES2018<'a, 'ctx> {
             self.object_rest_spread.enter_expression(expr, ctx);
         }
     }
+
+    fn enter_variable_declaration(
+        &mut self,
+        decl: &mut VariableDeclaration<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) {
+        if self.options.object_rest_spread.is_some() {
+            self.object_rest_spread.enter_variable_declaration(decl, ctx);
+        }
+    }
 }
diff --git a/crates/oxc_transformer/src/es2018/object_rest_spread.rs b/crates/oxc_transformer/src/es2018/object_rest_spread.rs
index ba174c84505560..1cebe7b0e1a6cb 100644
--- a/crates/oxc_transformer/src/es2018/object_rest_spread.rs
+++ b/crates/oxc_transformer/src/es2018/object_rest_spread.rs
@@ -29,7 +29,7 @@
 use serde::Deserialize;
 
 use oxc_ast::{ast::*, NONE};
-use oxc_semantic::{ReferenceFlags, SymbolId};
+use oxc_semantic::{ReferenceFlags, SymbolFlags, SymbolId};
 use oxc_span::SPAN;
 use oxc_traverse::{Traverse, TraverseCtx};
 
@@ -46,6 +46,7 @@ pub struct ObjectRestSpreadOptions {
 
 pub struct ObjectRestSpread<'a, 'ctx> {
     ctx: &'ctx TransformCtx<'a>,
+
     options: ObjectRestSpreadOptions,
 }
 
@@ -59,6 +60,14 @@ impl<'a, 'ctx> Traverse<'a> for ObjectRestSpread<'a, 'ctx> {
     fn enter_expression(&mut self, expr: &mut Expression<'a>, ctx: &mut TraverseCtx<'a>) {
         self.transform_object_expression(expr, ctx);
     }
+
+    fn enter_variable_declaration(
+        &mut self,
+        decl: &mut VariableDeclaration<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) {
+        self.transform_variable_declaration(decl, ctx);
+    }
 }
 
 impl<'a, 'ctx> ObjectRestSpread<'a, 'ctx> {
@@ -148,3 +157,52 @@ impl<'a, 'ctx> ObjectRestSpread<'a, 'ctx> {
         Expression::from(ctx.ast.member_expression_static(SPAN, object, property, false))
     }
 }
+
+impl<'a, 'ctx> ObjectRestSpread<'a, 'ctx> {
+    fn transform_variable_declaration(
+        &mut self,
+        decl: &mut VariableDeclaration<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) {
+        for variable_declarator in decl.declarations.iter_mut() {
+            self.transform_variable_declarator(variable_declarator, ctx);
+        }
+    }
+
+    fn transform_variable_declarator(
+        &mut self,
+        decl: &mut VariableDeclarator<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) {
+        // Get the object pattern.
+        let BindingPatternKind::ObjectPattern(pat) = &decl.id.kind else { return };
+        // Does not have a object rest.
+        let Some(rest) = &pat.rest else {
+            return;
+        };
+        // Rest binding is not an identifier (syntax error).
+        if !rest.argument.kind.is_binding_identifier() {
+            return;
+        }
+        // Does not have an init (syntax error).
+        let Some(init) = &decl.init else { return };
+
+        let binding = ctx
+            .generate_uid_in_current_scope_based_on_node(init, SymbolFlags::FunctionScopedVariable);
+
+        decl.id.kind = ctx
+            .ast
+            .binding_pattern_kind_from_binding_identifier(binding.create_binding_identifier(ctx));
+
+        // let mut new_declarators = ctx.ast.vec();
+
+        let BindingPatternKind::ObjectPattern(pat) = &mut decl.id.kind else { unreachable!() };
+        let BindingPatternKind::BindingIdentifier(rest_ident) = pat.rest.unwrap().argument.kind
+        else {
+            unreachable!()
+        };
+
+        // rest
+        dbg!(binding);
+    }
+}
diff --git a/crates/oxc_transformer/src/lib.rs b/crates/oxc_transformer/src/lib.rs
index a75fbd545e380d..8dbbd429a76985 100644
--- a/crates/oxc_transformer/src/lib.rs
+++ b/crates/oxc_transformer/src/lib.rs
@@ -159,6 +159,14 @@ impl<'a, 'ctx> Traverse<'a> for TransformerImpl<'a, 'ctx> {
         }
     }
 
+    fn enter_variable_declaration(
+        &mut self,
+        decl: &mut VariableDeclaration<'a>,
+        ctx: &mut TraverseCtx<'a>,
+    ) {
+        self.x2_es2018.enter_variable_declaration(decl, ctx);
+    }
+
     fn enter_variable_declarator(
         &mut self,
         decl: &mut VariableDeclarator<'a>,