Treemap Mark

treemap converts flat hierarchy rows into area-proportional leaf rectangles. It runs after the final plot bounds resolve, so tiling, padding, and labels use CSS pixels without application-owned coordinates or Cartesian scales.

import { treemap } from '@tanstack/charts/hierarchy/treemap'

const mark = treemap(rows, {
  path: 'name',
  delimiter: '.',
  value: 'size',
  color: (node) => node.ancestorIds.at(-1) ?? node.id,
  label: 'name',
  inset: 1,
  stroke: '#fff',
})

The exact optional subpath keeps hierarchy tiling out of root and ordinary-mark consumers.

Hierarchy input#

Path input constructs parent-child relationships from a string channel:

treemap(rows, {
  path: 'name',
  delimiter: '.',
  value: 'size',
})

Explicit parent references use nodeId because id is reserved for the mark:

treemap(rows, {
  id: 'package-sizes',
  nodeId: 'id',
  parentId: 'parentId',
  value: 'size',
})

Path input may omit ancestors. The mark imputes those structural nodes with data: null and empty direct lineage. Duplicate identities, invalid parents, multiple roots, and cycles throw before rendering. Authored child order is preserved unless sort is supplied.

Path-mode IDs use canonical slash form and name is the terminal path segment. Explicit-parent IDs are opaque, so name is the complete authored ID even when it contains a slash.

Options#

TreemapPathOptions<TDatum> and TreemapParentOptions<TDatum> form the TreemapOptions<TDatum> union.

Nullish values contribute zero. Other values must be nonnegative and finite. ratio is valid only with squarify. Padding, inset, and label padding are nonnegative CSS-pixel values.

Responsive layout#

Treemap row grouping depends on the final plot aspect ratio. The mark sizes the selected tiler to the resolved inner width and height on every layout pass; resizing may therefore change rectangle adjacency as well as dimensions. Coordinates use the screen convention where y increases downward and never enter a Cartesian scale.

Each pass lays out a private hierarchy copy. Value and path accessors are not rerun, input rows are not mutated, and repeated compilation at one size is deterministic. Stateful resquarify is intentionally not a method.

Nodes, labels, and interaction#

Only positive-area leaves render. Every rectangle and interaction point carries one TreemapNode<TDatum> with:

• stable id, parentId, and root-to-parent ancestorIds;
• name, depth, height, and internal / external metadata;
• aggregate value;
• the authored data row, or null for an imputed node; and
• direct source and sourceIndexes lineage.

Color, paint, state, and label channels receive these nodes. A label is emitted only when its measured bounds plus labelPadding fit inside the painted cell. This uses the chart host's text measurer when available and the deterministic scene estimator otherwise.

Types#

The exact entry exports treemap, TreemapMethod, TreemapNode, TreemapNodeComparator, TreemapPathOptions, TreemapParentOptions, and TreemapOptions.