0.9.1-alpha.63

Patch Changes

• 8bbed5d: feat(charts): LineChart, AreaChart, BarChart, PieChart and RadarChart — drawn here

  P5.34, P5.34b, P5.34e, P5.34f and P5.34g. Nothing is imported to draw them. react-native-svg is already an optional peer — the Select's check and the Icon's chevron use it — and everything above it is this library's: the scales, the paths, the palette.

  That is not an aesthetic preference. A chart library is a second design system: its own idea of a colour, its own appearance blob, its own units, and an API that is the one place variant and color cannot reach. Wrapping one means either exposing that blob — which is customAppearance, the thing R2 removed — or fighting it. The alternative considered was a native graphics engine as a peer dependency, which is a great deal of install for five figures.

  And the maths becomes tests. chart-scale, chart-path and chart-palette are 106 cases: a curve that must never dip below its data, an axis that must never label a value above the tallest bar, a bar whose corner must not exceed its own height, a ramp that must not drift off its hue. Each of those is a test rather than a screenshot someone has to remember to look at — and two of them were bugs the tests found before the demo did.

  The API is chartkit's shape — rows of objects, xKey, a key per series — with yKeys plural, because a chart with two series is the common case and not an escape hatch. The series are props, not children, and that is the one place this family parts company with the rest of the library: a line is not a component a caller composes, it is a column of their data. What composition there is lives on ChartPlot, which takes a render function.

  A shade per series, not a colour per series. The palette is walked out of one colour in OKLab lightness, and reduces chroma to stay in gamut rather than clamping channels — clamping gives away the hue, and a blue drifts several degrees towards cyan across a ramp. Shades of one colour say "parts of a whole" where a rainbow says "unrelated things", and it is the only scheme that survives a caller changing the accent.

  LineChart, AreaChart and BarChart are three files over one ChartPlot, the way the Autocomplete is a few files over selectRecipe. It owns the frame, the grid, the axes and both scales — point spacing for a line, band spacing for a bar, because a line inset by half a slot reads as cut off and a bar on the edge is half outside the plot. PieChart and RadarChart are square rather than framed, and take the palette and the ink to draw their own geometry.

  The axis is honest: niceScale picks a step from 1, 2, 2.5, 5 or 10 times a power of ten and then widens the domain to a multiple of it, rather than squeezing ticks into the data's own range — which is what produces an axis labelled 3.33, and how a top tick ends up below the tallest bar.

  The curve is Fritsch–Carlson: flat at every turning point, capped at three times the neighbouring slope elsewhere. A midpoint cubic is four lines and overshoots — two high readings either side of a low one bow the curve below the low one, and on an area chart that is ink under the axis.

  No chart paints its own ground; the card around it and the legend beside it are the caller's. tsup's DTS pass gets a larger heap, because the generic chart props push the default over.