Memory is seldom a constraint on the sorts of computers which run JS. The real WTF about that approach later on is just going to be that person.hasOwnProperty('

Memory is seldom a constraint on the sorts of computers which run JS. The real WTF about that approach later on is just going to be that person.hasOwnProperty('Save') === true. As long as you can guarantee that you will never want to iterate over a person with a for/in loop, you should be pretty much fine.