LibJS: Convert create_mutable_binding() to ThrowCompletionOr

Also add spec step comments to it while we're here.

1 files changed, 3 insertions, 2 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/ObjectEnvironment.cpp b/Userland/Libraries/LibJS/Runtime/ObjectEnvironment.cpp
index 301c398885..80f4230ae4 100644
--- a/Userland/Libraries/LibJS/Runtime/ObjectEnvironment.cpp
+++ b/Userland/Libraries/LibJS/Runtime/ObjectEnvironment.cpp
@@ -60,11 +60,12 @@ ThrowCompletionOr<bool> ObjectEnvironment::has_binding(FlyString const& name, Op
 }
 
 // 9.1.1.2.2 CreateMutableBinding ( N, D ), https://tc39.es/ecma262/#sec-object-environment-records-createmutablebinding-n-d
-void ObjectEnvironment::create_mutable_binding(GlobalObject&, FlyString const& name, bool can_be_deleted)
+ThrowCompletionOr<void> ObjectEnvironment::create_mutable_binding(GlobalObject&, FlyString const& name, bool can_be_deleted)
 {
     // 1. Let bindingObject be envRec.[[BindingObject]].
     // 2. Return ? DefinePropertyOrThrow(bindingObject, N, PropertyDescriptor { [[Value]]: undefined, [[Writable]]: true, [[Enumerable]]: true, [[Configurable]]: D }).
-    MUST(m_binding_object.define_property_or_throw(name, { .value = js_undefined(), .writable = true, .enumerable = true, .configurable = can_be_deleted }));
+    TRY(m_binding_object.define_property_or_throw(name, { .value = js_undefined(), .writable = true, .enumerable = true, .configurable = can_be_deleted }));
+    return {};
 }
 
 // 9.1.1.2.3 CreateImmutableBinding ( N, S ), https://tc39.es/ecma262/#sec-object-environment-records-createimmutablebinding-n-s