feat: grouped bar chart (aka stacked primary axis)

examples/simple/src/components/Bar.tsx

@@ -5,7 +5,7 @@ import { AxisOptions, Chart } from "react-charts";
 
 export default function Bar() {
   const { data, randomizeData } = useDemoConfig({
-    series: 10,
+    series: 3,
     dataType: "ordinal",
   });
 

examples/simple/src/components/BarHorizontal.tsx

@@ -5,7 +5,7 @@ import { AxisOptions, Chart } from "react-charts";
 
 export default function Bar() {
   const { data, randomizeData } = useDemoConfig({
-    series: 10,
+    series: 3,
     dataType: "ordinal",
   });
 

examples/simple/src/components/BarHorizontalStacked.tsx

@@ -0,0 +1,51 @@
+import ResizableBox from "../ResizableBox";
+import useDemoConfig from "../useDemoConfig";
+import React from "react";
+import { AxisOptions, Chart } from "react-charts";
+
+export default function BarHorizontalStacked() {
+  const { data, randomizeData } = useDemoConfig({
+    series: 10,
+    dataType: "ordinal",
+  });
+
+  const primaryAxis = React.useMemo<
+    AxisOptions<typeof data[number]["data"][number]>
+  >(
+    () => ({
+      position: "left",
+      getValue: (datum) => datum.primary,
+    }),
+    []
+  );
+
+  const secondaryAxes = React.useMemo<
+    AxisOptions<typeof data[number]["data"][number]>[]
+  >(
+    () => [
+      {
+        position: "bottom",
+        getValue: (datum) => datum.secondary,
+        stacked: true,
+      },
+    ],
+    []
+  );
+
+  return (
+    <>
+      <button onClick={randomizeData}>Randomize Data</button>
+      <br />
+      <br />
+      <ResizableBox>
+        <Chart
+          options={{
+            data,
+            primaryAxis,
+            secondaryAxes,
+          }}
+        />
+      </ResizableBox>
+    </>
+  );
+}

examples/simple/src/components/BarStacked.tsx

@@ -0,0 +1,49 @@
+import ResizableBox from "../ResizableBox";
+import useDemoConfig from "../useDemoConfig";
+import React from "react";
+import { AxisOptions, Chart } from "react-charts";
+
+export default function BarStacked() {
+  const { data, randomizeData } = useDemoConfig({
+    series: 10,
+    dataType: "ordinal",
+  });
+
+  const primaryAxis = React.useMemo<
+    AxisOptions<typeof data[number]["data"][number]>
+  >(
+    () => ({
+      getValue: (datum) => datum.primary,
+    }),
+    []
+  );
+
+  const secondaryAxes = React.useMemo<
+    AxisOptions<typeof data[number]["data"][number]>[]
+  >(
+    () => [
+      {
+        getValue: (datum) => datum.secondary,
+        stacked: true,
+      },
+    ],
+    []
+  );
+
+  return (
+    <>
+      <button onClick={randomizeData}>Randomize Data</button>
+      <br />
+      <br />
+      <ResizableBox>
+        <Chart
+          options={{
+            data,
+            primaryAxis,
+            secondaryAxes,
+          }}
+        />
+      </ResizableBox>
+    </>
+  );
+}

examples/simple/src/index.tsx

@@ -8,6 +8,7 @@ import ReactDOM from "react-dom";
 import Area from "./components/Area";
 import Band from "./components/Band";
 import Bar from "./components/Bar";
+import BarStacked from "./components/BarStacked";
 import Bubble from "./components/Bubble";
 import CustomStyles from "./components/CustomStyles";
 import DarkMode from "./components/DarkMode";
@@ -17,14 +18,17 @@ import Line from "./components/Line";
 import MultipleAxes from "./components/MultipleAxes";
 import Steam from "./components/Steam";
 import BarHorizontal from "./components/BarHorizontal";
+import BarHorizontalStacked from "./components/BarHorizontalStacked";
 import SparkChart from "./components/SparkChart";
 import SyncedCursors from "./components/SyncedCursors";
 import StressTest from "./components/StressTest";
 
 const components = [
   ["Line", Line],
   ["Bar", Bar],
+  ["Bar (Stacked)", BarStacked],
   ["Bar (Horizontal)", BarHorizontal],
+  ["Bar (Horizontal + Stacked)", BarHorizontalStacked],
   ["Band", Band],
   ["Area", Area],
   ["Bubble", Bubble],

examples/simple/src/styles.css

@@ -1,5 +1,10 @@
+body {
+  background: rgba(0, 0, 0, 0.02);
+}
+
 .react-resizable {
   max-width: 100%;
+  background: white;
 }
 
 .react-resizable-handle {

src/components/Chart.tsx

@@ -41,7 +41,7 @@ import Voronoi from './Voronoi'
 const defaultColorScheme = [
   '#0f83ab',
   '#faa43a',
-  '#ff4e4e',
+  '#fd6868',
   '#53cfc9',
   '#a2d925',
   '#decf3f',
@@ -263,7 +263,7 @@ function ChartInner<TDatum>({
         if (
           typeof optionsWithScaleType.stacked === 'undefined' &&
           optionsWithScaleType.elementType &&
-          ['bar', 'area'].includes(optionsWithScaleType.elementType)
+          ['area'].includes(optionsWithScaleType.elementType)
         ) {
           optionsWithScaleType.stacked = true
         }
@@ -276,6 +276,13 @@ function ChartInner<TDatum>({
     )
   }, [options.data, options.secondaryAxes, primaryAxisOptions])
 
+  if (
+    primaryAxisOptions.scaleType === 'band' &&
+    !secondaryAxesOptions.some(axisOptions => axisOptions.stacked)
+  ) {
+    primaryAxisOptions.stacked = primaryAxisOptions.stacked ?? true
+  }
+
   // Resolve Tooltip Option
   const tooltipOptions = React.useMemo(() => {
     const tooltipOptions = defaultTooltip(options?.tooltip)

src/types.ts

@@ -242,6 +242,8 @@ export type AxisOptionsBase = {
   tickCount?: number
   innerBandPadding?: number
   outerBandPadding?: number
+  innerSeriesBandPadding?: number
+  outerSeriesBandPadding?: number
   minBandSize?: number
   maxBandSize?: number
   minDomainLength?: number
@@ -346,6 +348,8 @@ export type ResolvedAxisOptions<TAxisOptions> = TSTB.Object.Required<
   | 'tickLabelRotationDeg'
   | 'innerBandPadding'
   | 'outerBandPadding'
+  | 'innerSeriesBandPadding'
+  | 'outerSeriesBandPadding'
   | 'show'
   | 'stacked'
 >
@@ -365,7 +369,8 @@ export type AxisTime<TDatum> = Omit<
   axisFamily: 'time'
   scale: ScaleTime<number, number, never>
   outerScale: ScaleTime<number, number, never>
-  bandScale?: ScaleBand<number>
+  primaryBandScale?: ScaleBand<number>
+  seriesBandScale?: ScaleBand<number>
   formatters: {
     default: (value: Date) => string
     scale: (value: Date) => string
@@ -381,7 +386,8 @@ export type AxisLinear<TDatum> = Omit<
   axisFamily: 'linear'
   scale: ScaleLinear<number, number, never>
   outerScale: ScaleLinear<number, number, never>
-  bandScale?: ScaleBand<number>
+  primaryBandScale?: ScaleBand<number>
+  seriesBandScale?: ScaleBand<number>
   formatters: {
     default: (value: ChartValue<any>) => string
     scale: (value: number) => string
@@ -397,6 +403,7 @@ export type AxisBand<TDatum> = Omit<
   axisFamily: 'band'
   scale: ScaleBand<any>
   outerScale: ScaleBand<any>
+  seriesBandScale: ScaleBand<number>
   formatters: {
     default: (value: any) => string
     scale: (value: any) => string

src/utils/Utils.ts

@@ -117,15 +117,14 @@ export function getPrimary<TDatum>(
   datum: Datum<TDatum>,
   primaryAxis: Axis<TDatum>
 ): number {
-  let primary: number
-
-  if (primaryAxis.stacked) {
-    primary = primaryAxis.scale(datum.stackData?.[1] ?? NaN) ?? NaN
-  } else {
-    primary = primaryAxis.scale(datum.primaryValue) ?? NaN
-  }
+  let primary = primaryAxis.scale(datum.primaryValue) ?? NaN
 
   if (primaryAxis.axisFamily === 'band') {
+    if (primaryAxis.stacked) {
+      primary =
+        primary + (primaryAxis.seriesBandScale(datum.seriesIndex) ?? NaN)
+    }
+
     primary = primary + getPrimaryLength(datum, primaryAxis) / 2
   }
 
@@ -146,13 +145,17 @@ export function getPrimaryLength<TDatum>(
   primaryAxis: Axis<TDatum>
 ) {
   if (primaryAxis.axisFamily === 'band') {
+    const bandWidth = primaryAxis.stacked
+      ? primaryAxis.seriesBandScale.bandwidth()
+      : primaryAxis.scale.bandwidth()
+
     return Math.min(
-      Math.max(primaryAxis.scale.bandwidth(), primaryAxis.minBandSize ?? 1),
+      Math.max(bandWidth, primaryAxis.minBandSize ?? 1),
       primaryAxis.maxBandSize ?? 99999999
     )
   }
 
-  return Math.max(primaryAxis.bandScale!.bandwidth(), 1)
+  return Math.max(primaryAxis.primaryBandScale!.bandwidth(), 1)
 }
 
 export function getSecondaryLength<TDatum>(