coerce Arrow BigInt to Number

src/options.js

@@ -69,6 +69,8 @@ function maybeTypedArrowify(vector, type) {
     ? vector
     : (type === undefined || type === Array) && isArrowDateType(vector.type)
     ? coerceDates(vector.toArray())
+    : (type === undefined || type === Array) && isArrowBigIntType(vector.type)
+    ? (type ?? Float64Array).from(vector.toArray(), Number)
     : maybeTypedArrayify(vector.toArray(), type);
 }
 
@@ -625,6 +627,7 @@ function isArrowVector(value) {
 // Apache Arrow now represents dates as numbers. We currently only support
 // implicit coercion to JavaScript Date objects when the numbers represent
 // milliseconds since Unix epoch.
+// https://github.com/apache/arrow/blob/cd50c324882ab1419d1728e9adad20d47b185508/js/src/enum.ts#L52-L72
 function isArrowDateType(type) {
   return (
     type &&
@@ -633,3 +636,12 @@ function isArrowDateType(type) {
     type.unit === 1 // millisecond
   );
 }
+
+// https://github.com/apache/arrow/blob/cd50c324882ab1419d1728e9adad20d47b185508/js/src/enum.ts#L52-L72
+function isArrowBigIntType(type) {
+  return (
+    type &&
+    type.typeId === 2 && // int
+    type.bitWidth >= 64
+  );
+}

test/plots/bigint.ts

@@ -1,5 +1,6 @@
 import * as Plot from "@observablehq/plot";
 import * as d3 from "d3";
+import * as Arrow from "apache-arrow";
 
 const integers = d3.range(40).map((int) => ({
   big1: BigInt(int),
@@ -25,3 +26,21 @@ export async function bigintOrdinal() {
 export async function bigintStack() {
   return Plot.barY(integers, {x: (d, i) => i % 5, y: "big1"}).plot();
 }
+
+export async function bigintNormalize() {
+  const heights = await d3.csv("data/athletes.csv").then((data) => data.map((d) => d.height));
+  const table = Arrow.tableFromJSON(
+    d3.groups(heights, (d) => (d ? +d : NaN)).map(([height, {length}]) => ({height, frequency: BigInt(length)}))
+  );
+  return Plot.plot({
+    height: 500,
+    x: {percent: true, grid: true},
+    marks: [
+      Plot.ruleX([0]),
+      Plot.ruleY(
+        table,
+        Plot.normalizeX("sum", {strokeWidth: 2, y: "height", x: "frequency", tip: {format: {y: ".2f"}}})
+      )
+    ]
+  });
+}