Query Design — Separation of Data and Presentation

DAX computes and fetches data. TypeScript shapes it for display. VegaVisual and DataGrid render it.

Aggregate in DAX to the visual's grain — never fetch lower-grain rows to roll up client-side. Once at the visual's grain, TypeScript can derive simple totals (SUM, COUNT, MIN, MAX) from the already-fetched detail rows. When a visual layout changes, only the TypeScript or spec layer should change — not the DAX query.

Responsibility Matrix