From 6f52949210ee2a71ed119cbcdf2db1842a2e63cb Mon Sep 17 00:00:00 2001
From: Austaras <austaras@outlook.com>
Date: Sat, 12 Oct 2024 15:07:08 +0800
Subject: [PATCH] fix(es/minifier): Only merge last if return (#9633)

**Related issue:**
 - Closes https://github.com/swc-project/swc/issues/9628
---
 .changeset/good-lions-design.md                       |  6 ++++++
 .../src/compress/optimize/if_return.rs                |  6 +++---
 .../tests/fixture/issues/9628/input.js                | 11 +++++++++++
 .../tests/fixture/issues/9628/output.js               |  1 +
 4 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/good-lions-design.md
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/9628/input.js
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/9628/output.js

diff --git a/.changeset/good-lions-design.md b/.changeset/good-lions-design.md
new file mode 100644
index 000000000000..15b155573d1e
--- /dev/null
+++ b/.changeset/good-lions-design.md
@@ -0,0 +1,6 @@
+---
+swc_core: patch
+swc_ecma_minifier: patch
+---
+
+fix(es/minifier): Only merge last if return
diff --git a/crates/swc_ecma_minifier/src/compress/optimize/if_return.rs b/crates/swc_ecma_minifier/src/compress/optimize/if_return.rs
index e5ad4d9de2b5..e7fe6b811c22 100644
--- a/crates/swc_ecma_minifier/src/compress/optimize/if_return.rs
+++ b/crates/swc_ecma_minifier/src/compress/optimize/if_return.rs
@@ -494,16 +494,16 @@ impl Optimizer<'_> {
         }
     }
 
-    fn can_merge_stmt_as_if_return(&self, s: &Stmt, _is_last: bool) -> bool {
+    fn can_merge_stmt_as_if_return(&self, s: &Stmt, is_last: bool) -> bool {
         // if !res {
         //     trace!("Cannot merge: {}", dump(s));
         // }
 
         match s {
             Stmt::Expr(..) => true,
-            Stmt::Return(..) => true,
+            Stmt::Return(..) => is_last,
             Stmt::Block(s) => {
-                s.stmts.len() == 1 && self.can_merge_stmt_as_if_return(&s.stmts[0], false)
+                s.stmts.len() == 1 && self.can_merge_stmt_as_if_return(&s.stmts[0], is_last)
             }
             Stmt::If(stmt) => {
                 matches!(&*stmt.cons, Stmt::Return(..))
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/9628/input.js b/crates/swc_ecma_minifier/tests/fixture/issues/9628/input.js
new file mode 100644
index 000000000000..d72cd31502f7
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/9628/input.js
@@ -0,0 +1,11 @@
+const getString = () => {
+    switch ("apple") {
+        case "apple":
+            return "1";
+        case "banana":
+            return "2";
+    }
+    return "3";
+};
+
+console.log(getString());
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/9628/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/9628/output.js
new file mode 100644
index 000000000000..eaedf96c62f6
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/9628/output.js
@@ -0,0 +1 @@
+console.log("1");