A constructor function would be a typical way to refer to it
However, you could call it a class and I highly doubt anyone would argue with you in a practical or workplace setting. It's still essentially a class in concept, even if Javascript doesn't implement it as such - anybody seeing that code would understand that you were making an object based on a class-like definition.
The implementation is clearly different, but the intent is (near enough) the same, and it's pretty fair to use the same name. If nothing else, it's less likely to cause confusion
I make no promises over whether someone would argue with you over it in a research or academic setting....
