depends. if you need to expose your data trough api your api will likely follow the relational model. it's then more convenient for the interpretation to happen

depends. if you need to expose your data trough api your api will likely follow the relational model. it's then more convenient for the interpretation to happen in the presentation layer. or, splitting hair, yeah if the ui needs some hierarchy rendered out of a flat table then the javascript controller should transform it before passing to the renderer. depends where you place the cut at this point.