> Like surely I can’t prevent any new array methods from ever existing by making a website with a list of known array prototype properties and throwing an error

> Like surely I can’t prevent any new array methods from ever existing by making a website with a list of known array prototype properties and throwing an error if any new ones show up, right? No, and that’s not what’s happening here. MooTools was very popular and is still used on many websites. They are adding ‘flat’ even though in some obscure corner of the internet that’s going to break something.