State and presets

NicePool uses explicit JSON-compatible state rather than treating controls as the source of truth. TypeScript interfaces describe authoring-time types, runtime validators reject incompatible data atomically, and the version-one JSON Schemas in schemas/ provide the cross-language contract.

Workspace state

NicePoolState stores schemaVersion, layout, active plot index, and exactly four independent PlotState objects. Layout is one of 1x1, 1x2, 2x1, or 2x2. Hidden plot slots remain intact when the layout changes. One shared control panel edits only the active visible plot.

Defaults must be derived after dataset validation because valid X, Y, Group, and Color-by choices depend on the table schema. setData therefore creates a fresh default workspace and clears selection; it never attempts to carry plot state across datasets.

Plot-type-specific fields remain present while inactive. This keeps the state simple, stable, and easy for Python or TypeScript clients to construct.

Display fields are also plot state: legend visibility and position, Plotly toolbar visibility, combined axis chrome, and horizontal/vertical grid lines. They are represented by showLegend, legendPosition, showPlotlyToolbar, showAxes, showHorizontalGrid, and showVerticalGrid. The default legend position is bottom.

Light/dark theme, splitter positions, and the open/closed Display options panel are workspace presentation settings rather than analytical plot state. They do not enter presets or summaries. The default theme is dark.

Plot presets

A PlotPreset has a version, name, and one complete PlotState. Applying it replaces only the active plot. The standalone demo may persist presets in browser local storage, but persistence is optional presentation behavior; the engine only validates and applies values supplied by its caller.

Preset validation is dataset-aware. A preset referring to an absent or incompatible column fails as a whole rather than partially changing the plot. Complete workspace save/load is intentionally deferred until a concrete client workflow requires it.