Impl `propertyIsEnumerable`

core/src/avm2/function.rs

@@ -571,6 +571,10 @@ impl<'gc> TObject<'gc> for FunctionObject<'gc> {
         self.0.read().base.get_enumerant_name(index)
     }
 
+    fn property_is_enumerable(&self, name: &QName) -> bool {
+        self.0.read().base.property_is_enumerable(name)
+    }
+
     fn as_ptr(&self) -> *const ObjectPtr {
         self.0.as_ptr() as *const ObjectPtr
     }

core/src/avm2/globals/object.rs

@@ -64,6 +64,28 @@ pub fn is_prototype_of<'gc>(
     Ok(false.into())
 }
 
+/// `Object.prototype.propertyIsEnumerable`
+pub fn property_is_enumerable<'gc>(
+    _avm: &mut Avm2<'gc>,
+    _context: &mut UpdateContext<'_, 'gc, '_>,
+    this: Option<Object<'gc>>,
+    args: &[Value<'gc>],
+) -> Result<ReturnValue<'gc>, Error> {
+    let this: Result<Object<'gc>, Error> = this.ok_or_else(|| "No valid this parameter".into());
+    let this = this?;
+    let name: Result<&Value<'gc>, Error> = args.get(0).ok_or_else(|| "No name specified".into());
+    let name = name?.as_string()?;
+
+    if let Some(ns) = this.resolve_any(&name)? {
+        if !ns.is_private() {
+            let qname = QName::new(ns, &name);
+            return Ok(this.property_is_enumerable(&qname).into());
+        }
+    }
+
+    Ok(false.into())
+}
+
 /// Partially construct `Object.prototype`.
 ///
 /// `__proto__` and other cross-linked properties of this object will *not*
@@ -90,4 +112,10 @@ pub fn fill_proto<'gc>(
         0,
         FunctionObject::from_builtin(gc_context, is_prototype_of, fn_proto),
     );
+    object_proto.install_method(
+        gc_context,
+        QName::new(Namespace::public_namespace(), "propertyIsEnumerable"),
+        0,
+        FunctionObject::from_builtin(gc_context, property_is_enumerable, fn_proto),
+    );
 }

core/src/avm2/object.rs

@@ -352,6 +352,11 @@ pub trait TObject<'gc>: 'gc + Collect + Debug + Into<Object<'gc>> + Clone + Copy
     /// mechanism.
     fn get_enumerant_name(&self, index: u32) -> Option<QName>;
 
+    /// Determine if a property is currently enumerable.
+    ///
+    /// Properties that do not exist are also not enumerable.
+    fn property_is_enumerable(&self, name: &QName) -> bool;
+
     /// Install a method (or any other non-slot value) on an object.
     fn install_method(
         &mut self,

core/src/avm2/script_object.rs

@@ -202,6 +202,10 @@ impl<'gc> TObject<'gc> for ScriptObject<'gc> {
         self.0.read().get_enumerant_name(index)
     }
 
+    fn property_is_enumerable(&self, name: &QName) -> bool {
+        self.0.read().property_is_enumerable(name)
+    }
+
     fn as_ptr(&self) -> *const ObjectPtr {
         self.0.as_ptr() as *const ObjectPtr
     }
@@ -750,6 +754,10 @@ impl<'gc> ScriptObjectData<'gc> {
         self.enumerants.get(true_index).cloned()
     }
 
+    pub fn property_is_enumerable(&self, name: &QName) -> bool {
+        self.enumerants.contains(name)
+    }
+
     /// Install a method into the object.
     pub fn install_method(&mut self, name: QName, disp_id: u32, function: Object<'gc>) {
         if disp_id > 0 {