Does `<data class>.copy` do anything special...

# announcements

[eygraber]

Does <data class>.copy do anything special in terms of GC, or is it the same as allocating a new object?

If I have a list of objects that are instances of data classes in a performance critical part of my code, and I need to routinely update the value of one of their fields, would I be better off making it a var and updating it in place, or using copy?

[spand]

copy allocates a new object as the name suggests. If there is no need for a copy then mutating the property might be a good idea

[edwardwongtl]

I would use a var in this case, it can save lots of memory if your object is huge.