feat: add sugar method for PropertyLValue (#1651)

Author: neko-para

napi-inl.h

@@ -1577,6 +1577,11 @@ inline Object::PropertyLValue<Key>& Object::PropertyLValue<Key>::operator=(
   return *this;
 }
 
+template <typename Key>
+inline Value Object::PropertyLValue<Key>::AsValue() const {
+  return Value(*this);
+}
+
 template <typename Key>
 inline Object::PropertyLValue<Key>::PropertyLValue(Object object, Key key)
     : _env(object.Env()), _object(object), _key(key) {}

napi.h

@@ -860,6 +860,9 @@ class Object : public TypeTaggable {
     template <typename ValueType>
     PropertyLValue& operator=(ValueType value);
 
+    /// Converts an L-value to a value. For convenience.
+    Value AsValue() const;
+
    private:
     PropertyLValue() = delete;
     PropertyLValue(Object object, Key key);