OptionalgaugeThe Gauge draw options — the same object passed to chart.draw(…).
A dial's range and its coloured bands live there and nowhere else, and they are most of what a gauge means: without them the reading is a bare number with nothing to sit against.
OptionalstepWhere a 'SurvivalChart' jumps between samples — 'hv' for a curve that
holds its value until the next event, which is what a Kaplan-Meier
estimate does.
Omit it when you are not sure: MAIDR substitutes no default, so the description stays silent about the convention rather than naming one the chart never authored.
OptionalthresholdThe cutoffs a 'VolcanoChart' or 'ManhattanChart' is read through —
the significance line, which side of it counts, and the effect size.
These charts carry tens of thousands of points of which a few dozen matter, and the thresholds are what make those few reachable: they drive the summary on entry and the rotor filter that jumps between the hits. They live in the plotted reference lines and in the analysis, never in the DataTable, and MAIDR guesses none — a line at the wrong place would sort every point on the figure onto the wrong side of it, silently.
OptionalwaterfallWhich rows of a 'WaterfallChart' restate the running total rather than
changing it — the opening and closing bars, and any subtotal drawn along
the way, by DataTable row index.
Cannot be inferred: a subtotal's start and end are ordinary numbers, and a reader told a subtotal "rose by 950" hears a contribution the chart never made.
The facts a chart's reading needs that live in the draw options rather than in the DataTable, and so have to be handed to the adapter separately.
Shared by the single-chart and multi-panel entry points, since a panel of a faceted figure may be any of the chart types that need them.