From ff440157a0a7cba215d99caad3c92d11a6d51ad1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Thu, 18 Jun 2020 17:04:49 +0900
Subject: [PATCH] Fix regenerator (#851)

swc_ecma_transforms:
 - Fix regenerator scoping issue.
---
 .../src/compat/es2015/regenerator/mod.rs      | 30 +++++++++++--------
 ecmascript/transforms/tests/es2015_classes.rs | 23 ++++++++++++++
 .../transforms/tests/es2015_regenerator.rs    | 11 +++++++
 node-swc/__tests__/transform/issue846_test.js | 24 +++++++++++++++
 package.json                                  |  2 +-
 5 files changed, 77 insertions(+), 13 deletions(-)
 create mode 100644 node-swc/__tests__/transform/issue846_test.js

diff --git a/ecmascript/transforms/src/compat/es2015/regenerator/mod.rs b/ecmascript/transforms/src/compat/es2015/regenerator/mod.rs
index 2d21bbeed70..b44df3c17d2 100644
--- a/ecmascript/transforms/src/compat/es2015/regenerator/mod.rs
+++ b/ecmascript/transforms/src/compat/es2015/regenerator/mod.rs
@@ -85,21 +85,27 @@ where
             return items;
         }
 
-        let mut items = items.fold_children(self);
+        let mut new = Vec::with_capacity(items.len() + 2);
 
-        if !self.top_level_vars.is_empty() {
-            prepend(
-                &mut items,
-                T::from_stmt(Stmt::Decl(Decl::Var(VarDecl {
-                    span: DUMMY_SP,
-                    kind: VarDeclKind::Var,
-                    declare: false,
-                    decls: replace(&mut self.top_level_vars, Default::default()),
-                }))),
-            );
+        for item in items {
+            let item = item.fold_with(self);
+
+            if !self.top_level_vars.is_empty() {
+                prepend(
+                    &mut new,
+                    T::from_stmt(Stmt::Decl(Decl::Var(VarDecl {
+                        span: DUMMY_SP,
+                        kind: VarDeclKind::Var,
+                        declare: false,
+                        decls: replace(&mut self.top_level_vars, Default::default()),
+                    }))),
+                );
+            }
+
+            new.push(item);
         }
 
-        items
+        new
     }
 }
 
diff --git a/ecmascript/transforms/tests/es2015_classes.rs b/ecmascript/transforms/tests/es2015_classes.rs
index 4522e4dc703..bd1abfe7b33 100644
--- a/ecmascript/transforms/tests/es2015_classes.rs
+++ b/ecmascript/transforms/tests/es2015_classes.rs
@@ -6109,3 +6109,26 @@ with (env) {
 
 "#
 );
+
+test_exec!(
+    syntax(),
+    |_| Classes::default(),
+    issue_846,
+    r#"
+class SomeClass {
+  someMethod() {
+     return 1;
+  }
+}
+
+class OtherClass extends SomeClass {
+  anotherMethod() {
+    expect(super.someMethod()).toBe(1);
+    return 2;
+  }
+}
+
+const obj = new OtherClass();
+expect(obj.anotherMethod()).toBe(2);
+"#
+);
diff --git a/ecmascript/transforms/tests/es2015_regenerator.rs b/ecmascript/transforms/tests/es2015_regenerator.rs
index 8cb2d473c1e..75897989301 100644
--- a/ecmascript/transforms/tests/es2015_regenerator.rs
+++ b/ecmascript/transforms/tests/es2015_regenerator.rs
@@ -1116,3 +1116,14 @@ export function myGenerator() {
 }
 "
 );
+
+test_exec!(
+    syntax(),
+    |_| es2015::regenerator(Mark::fresh(Mark::root())),
+    issue_849_1,
+    "function* gen() { yield 1 };
+function genFactory() { return function*() { yield 1 }; }
+const v = genFactory()();
+expect(v.next()).toEqual({ value: 1, done: false })
+expect(v.next()).toEqual({ done: true })"
+);
diff --git a/node-swc/__tests__/transform/issue846_test.js b/node-swc/__tests__/transform/issue846_test.js
new file mode 100644
index 00000000000..f508978b582
--- /dev/null
+++ b/node-swc/__tests__/transform/issue846_test.js
@@ -0,0 +1,24 @@
+const swc = require('../../../');
+
+
+it("should handle es2019", () => {
+  expect(
+    swc.transformSync(`class SomeClass {
+  someMethod() {}
+}
+
+class OtherClass extends SomeClass {
+  anotherMethod() {
+    super.someMethod()
+  }
+}`, {
+      jsc: {
+        parser: {
+          syntax: "ecmascript",
+        },
+        target: "es2019",
+      }
+    })
+      .code.trim()
+  ).toContain(`class `);
+});
\ No newline at end of file
diff --git a/package.json b/package.json
index 44965587e3d..7e4f622f7c6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@swc/core",
-  "version": "1.2.4",
+  "version": "1.2.5",
   "description": "Super-fast alternative for babel",
   "main": "./index.js",
   "author": "강동윤 <kdy1997.dev@gmail.com>",