Column footer

A column footer pins a grand-total row below the scroll area so the whole-frame aggregate for each measure stays visible while you scroll and expand. It is computed over the source frame (the engine’s true grand total, not a client-side sum of pre-aggregated leaves, which would give a mean-of-means), and it stays put through the windowed re-render of a virtualized grid.

Dash (Python)

from dash_tensor_grid import GridDataEngine, TensorGrid, build_payload

# Compute the footer with the engine so tree mode gets the true whole-frame totals.
engine = GridDataEngine(sales)
payload = build_payload(engine, {
    "rows": ["region", "country"],
    "measures": {"revenue": "sum", "qty": "sum"},
    "formats": {"revenue": "currency:USD", "qty": "number:0"},
})
TensorGrid(
    id="grid",
    row_data=payload["row_data"],
    column_defs=payload["column_defs"],
    show_footer=True,
    footer=engine.column_footer({"revenue": "sum", "qty": "sum"}),
)

React

<TensorGrid
  data={data}
  rows={['region', 'country']}
  measures={{ revenue: 'sum', qty: 'sum' }}
  formats={{ revenue: '$0,0', qty: '0,0' }}
  showFooter
  footerLabel="Grand total"
/>;

Vue

<TensorGrid
  :data="data"
  :rows="['region', 'country']"
  :measures="{ revenue: 'sum', qty: 'sum' }"
  :formats="{ revenue: '$0,0', qty: '0,0' }"
  show-footer
  footer-label="Grand total"
/>

Vanilla JS

mountTensorGrid(el, {
  data,
  rows: ['region', 'country'],
  measures: { revenue: 'sum', qty: 'sum' },
  formats: { revenue: '$0,0', qty: '0,0' },
  showFooter: true,
  footerLabel: 'Grand total',
});

Notes

• The engine owns the totals. The JS adapters derive the footer via the core whole-frame aggregate; in Dash you pass explicit footer values (here engine.column_footer(...)), so a tree-mode grid shows the correct grand total rather than an average of subtotals.
• footerLabel (adapters) / the footer’s group cell names the row (default “Total”).
• The footer sticks to the bottom of the scroll container and is re-applied after each virtualized render, so it never scrolls out of view. It also works on the virtualized grid.
• Want a total row inside the tree instead of a pinned footer? Use grandTotal on aggregation, or a pinned column to keep the label column frozen on horizontal scroll.