From c0a3ddac28a91a2a6d5aca0b9e4b65180dae6380 Mon Sep 17 00:00:00 2001
From: Boshen <1430279+Boshen@users.noreply.github.com>
Date: Thu, 9 Jan 2025 06:49:27 +0000
Subject: [PATCH] fix(minifier): `instanceof` has error throwing side effect
 (#8378)

---
 .../src/side_effects/check_for_state_change.rs        | 11 ++++++++---
 .../src/ast_passes/peephole_remove_dead_code.rs       |  1 +
 crates/oxc_syntax/src/operator.rs                     |  5 +++++
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/crates/oxc_ecmascript/src/side_effects/check_for_state_change.rs b/crates/oxc_ecmascript/src/side_effects/check_for_state_change.rs
index 07134b57b37f2..5a24c95ef7563 100644
--- a/crates/oxc_ecmascript/src/side_effects/check_for_state_change.rs
+++ b/crates/oxc_ecmascript/src/side_effects/check_for_state_change.rs
@@ -95,10 +95,15 @@ impl<'a> CheckForStateChange<'a, '_> for UnaryExpression<'a> {
 
 impl<'a> CheckForStateChange<'a, '_> for BinaryExpression<'a> {
     fn check_for_state_change(&self, check_for_new_objects: bool) -> bool {
+        // `instanceof` can throw `TypeError`
+        if self.operator.is_instance_of() {
+            return true;
+        }
         let left = self.left.check_for_state_change(check_for_new_objects);
-        let right = self.right.check_for_state_change(check_for_new_objects);
-
-        left || right
+        if left {
+            return true;
+        }
+        self.right.check_for_state_change(check_for_new_objects)
     }
 }
 
diff --git a/crates/oxc_minifier/src/ast_passes/peephole_remove_dead_code.rs b/crates/oxc_minifier/src/ast_passes/peephole_remove_dead_code.rs
index 98e5d233c5d66..52b15ba339154 100644
--- a/crates/oxc_minifier/src/ast_passes/peephole_remove_dead_code.rs
+++ b/crates/oxc_minifier/src/ast_passes/peephole_remove_dead_code.rs
@@ -717,6 +717,7 @@ mod test {
         fold("(function k() {}, k(), baz())", "k(), baz()");
         fold_same("(0, o.f)();");
         fold("var obj = Object((null, 2, 3), 1, 2);", "var obj = Object(3, 1, 2);");
+        fold_same("(0 instanceof 0, foo)");
     }
 
     #[test]
diff --git a/crates/oxc_syntax/src/operator.rs b/crates/oxc_syntax/src/operator.rs
index 70aa66ef039df..264745ffe1f6d 100644
--- a/crates/oxc_syntax/src/operator.rs
+++ b/crates/oxc_syntax/src/operator.rs
@@ -268,6 +268,11 @@ impl BinaryOperator {
         self == Self::In
     }
 
+    /// Returns `true` if this is an [`In`](BinaryOperator::Instanceof) operator.
+    pub fn is_instance_of(self) -> bool {
+        self == Self::Instanceof
+    }
+
     /// Returns `true` for any bitwise operator
     #[rustfmt::skip]
     pub fn is_bitwise(self) -> bool {