Where To Format?

I'm using Laravel, with Api Resources and Inertia.

I need to format some of my data, for example date formatting for humans.

I considered doing it JS side, but as the same data appears in several places I want consistency.

So where to put it? Model accessor? Api Resource? Somewhere else?

Not, I cannot overwrite the original value, as I still need to retain it (for the date example, it may need editing by the user).