fix tree.js and add various tests

src/transforms/tree.js

@@ -1,6 +1,6 @@
 import {stratify, tree} from "d3";
 import {ascendingDefined} from "../defined.js";
-import {column, identity, isObject, one, valueof} from "../options.js";
+import {column, identity, isArray, isObject, one, valueof} from "../options.js";
 import {basic} from "./basic.js";
 
 export function treeNode({
@@ -40,7 +40,9 @@ export function treeNode({
       for (const o of outputs) o[output_values] = o[output_setValues]([]);
       for (const facet of facets) {
         const treeFacet = [];
-        const root = rootof(facet.filter((i) => P[i] != null)).each((node) => (node.data = data[node.data]));
+        const root = rootof(facet.filter((i) => P[i] != null)).each(
+          isArray(data) ? (node) => (node.data = data[node.data]) : (node) => (node.data = data.get(node.data))
+        );
         if (treeSort != null) root.sort(treeSort);
         layout(root);
         for (const node of root.descendants()) {

test/plots/arrow.ts

@@ -50,3 +50,100 @@ export async function arrowTestGroup() {
   const data = Arrow.tableFromArrays({category, vector});
   return Plot.barY(data, Plot.groupX({y: "count"}, {x: "vector", fill: "category"})).plot({marginLeft: 60});
 }
+
+/**
+ * An arrow table dataset supports sorting with a comparator.
+ */
+export async function arrowTestSort() {
+  const data = Arrow.tableFromArrays({
+    id: [1, 2, 3],
+    name: ["Alice", "Bob", "Charlie"],
+    age: [35, 25, 45]
+  });
+  return Plot.barX(data, {x: "age", fill: "name", sort: (a: {age: number}, b: {age: number}) => b.age - a.age}).plot();
+}
+
+/**
+ * An arrow table dataset supports accessing the node's datum.
+ */
+export async function arrowTestTree() {
+  const gods = Arrow.tableFromArrays({
+    branch: `Chaos Gaia Mountains
+Chaos Gaia Pontus
+Chaos Gaia Uranus
+Chaos Eros
+Chaos Erebus
+Chaos Tartarus`
+      .split("\n")
+      .map((d) => d.replace(/\s+/g, "/"))
+  });
+  return Plot.plot({
+    axis: null,
+    insetLeft: 35,
+    insetTop: 20,
+    insetBottom: 20,
+    insetRight: 120,
+    marks: [Plot.tree(gods, {path: "branch", fill: (d) => d?.branch})]
+  });
+}
+
+/**
+ * An arrow table dataset supports Plot.find.
+ */
+export async function arrowTestDifferenceY() {
+  const stocks = Arrow.tableFromJSON(await readStocks());
+  return Plot.plot({
+    marks: [
+      Plot.differenceY(
+        stocks,
+        Plot.normalizeY(
+          Plot.groupX(
+            {y1: Plot.find((d) => d.Symbol === "GOOG"), y2: Plot.find((d) => d.Symbol === "AAPL")},
+            {x: "Date", y: "Close", tip: true}
+          )
+        )
+      )
+    ]
+  });
+}
+
+async function readStocks(start = 0, end = Infinity) {
+  return (
+    await Promise.all(
+      ["AAPL", "GOOG"].map((symbol) =>
+        d3.csv<any>(`data/${symbol.toLowerCase()}.csv`, (d, i) =>
+          start <= i && i < end ? ((d.Symbol = symbol), d3.autoType(d)) : null
+        )
+      )
+    )
+  ).flat();
+}
+
+/**
+ * An arrow table dataset supports stack custom order.
+ */
+export async function arrowTestCustomOrder() {
+  const riaa = Arrow.tableFromJSON(await d3.csv<any>("data/riaa-us-revenue.csv", d3.autoType));
+  return Plot.plot({
+    y: {
+      grid: true,
+      label: "Annual revenue (billions, adj.)",
+      transform: (d) => d / 1000
+    },
+    marks: [
+      Plot.areaY(
+        riaa,
+        Plot.stackY({
+          x: "year",
+          y: "revenue",
+          z: "format",
+          order: (a, b) => d3.ascending(a.group, b.group) || d3.descending(a.revenue, b.revenue),
+          fill: "group",
+          stroke: "white",
+          title: (d) => `${d.format}\n${d.group}`
+        })
+      ),
+      Plot.ruleY([0])
+    ]
+  });
+}