From 0975e082858af4114c3f953c32f4440ab407e8b1 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gbeutner@serenityos.org>
Date: Tue, 8 Jun 2021 11:30:57 +0200
Subject: [PATCH] LibJS: Make if yield undefined for the else branch if it is
 missing

---
 Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
index dfd2768821..e473aadf73 100644
--- a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
+++ b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
@@ -397,6 +397,8 @@ Optional<Bytecode::Register> IfStatement::generate_bytecode(Bytecode::Generator&
     if (m_alternate) {
         auto alternative_reg = m_alternate->generate_bytecode(generator);
         generator.emit<Bytecode::Op::LoadRegister>(result_reg, *alternative_reg);
+    } else {
+        generator.emit<Bytecode::Op::Load>(result_reg, js_undefined());
     }
 
     end_jump.set_target(generator.make_label());