Core Concepts
Model hierarchy, navigation, colors, and selection.
Hierarchy and drill-down
A node with children is a group. Tapping its header drills into that group by default. Keep HeatmapState hoisted and call navigateUp() from platform Back handling.
Area and color
value always determines relative rectangle area. metric is optional and can represent a return, error rate, variance, health score, or any signed domain indicator. Use SignedMetricColorScale or provide a custom HeatmapColorScale.
Selection
Leaf taps select by default. Read state.selectedNode to show a detail panel, then call clearSelection() when it closes.