From 2c6e052f5bae042c3b25fdecf15c0df201734f37 Mon Sep 17 00:00:00 2001
From: Mike Bostock <mbostock@gmail.com>
Date: Sat, 15 Jun 2024 18:34:29 -0700
Subject: [PATCH 1/2] more geojson-aware

---
 src/marks/geo.js                   | 18 ------------------
 src/options.js                     | 22 +++++++++++++++++++---
 test/plots/country-centroids.ts    |  2 +-
 test/plots/us-county-choropleth.ts |  2 +-
 4 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/src/marks/geo.js b/src/marks/geo.js
index e986539377..903794406d 100644
--- a/src/marks/geo.js
+++ b/src/marks/geo.js
@@ -67,24 +67,6 @@ function scaleProjection({x: X, y: Y}) {
 }
 
 export function geo(data, {geometry = identity, ...options} = {}) {
-  switch (data?.type) {
-    case "FeatureCollection":
-      data = data.features;
-      break;
-    case "GeometryCollection":
-      data = data.geometries;
-      break;
-    case "Feature":
-    case "LineString":
-    case "MultiLineString":
-    case "MultiPoint":
-    case "MultiPolygon":
-    case "Point":
-    case "Polygon":
-    case "Sphere":
-      data = [data];
-      break;
-  }
   return new Geo(data, {geometry, ...options});
 }
 
diff --git a/src/options.js b/src/options.js
index a170e4c003..d7abbadf0e 100644
--- a/src/options.js
+++ b/src/options.js
@@ -47,7 +47,7 @@ function floater(f) {
 }
 
 export const singleton = [null]; // for data-less decoration marks, e.g. frame
-export const field = (name) => (d) => d[name];
+export const field = (name) => (d) => { const v = d[name]; return v === undefined && d.type === "Feature" ? d.properties?.[name] : v; }; // prettier-ignore
 export const indexOf = {transform: range};
 export const identity = {transform: (d) => d};
 export const zero = () => 0;
@@ -131,8 +131,24 @@ export function keyword(input, name, allowed) {
 }
 
 // Promotes the specified data to an array as needed.
-export function arrayify(data) {
-  return data == null || data instanceof Array || data instanceof TypedArray ? data : Array.from(data);
+export function arrayify(values) {
+  if (values == null || values instanceof Array || values instanceof TypedArray) return values;
+  switch (values.type) {
+    case "FeatureCollection":
+      return values.features;
+    case "GeometryCollection":
+      return values.geometries;
+    case "Feature":
+    case "LineString":
+    case "MultiLineString":
+    case "MultiPoint":
+    case "MultiPolygon":
+    case "Point":
+    case "Polygon":
+    case "Sphere":
+      return [values];
+  }
+  return Array.from(values);
 }
 
 // An optimization of type.from(values, f): if the given values are already an
diff --git a/test/plots/country-centroids.ts b/test/plots/country-centroids.ts
index 2d61f236cd..55dd28a407 100644
--- a/test/plots/country-centroids.ts
+++ b/test/plots/country-centroids.ts
@@ -5,7 +5,7 @@ import {feature} from "topojson-client";
 export async function countryCentroids() {
   const world = await d3.json<any>("data/countries-110m.json");
   const land = feature(world, world.objects.land);
-  const countries = feature(world, world.objects.countries).features;
+  const countries = feature(world, world.objects.countries);
   return Plot.plot({
     projection: "mercator",
     marks: [
diff --git a/test/plots/us-county-choropleth.ts b/test/plots/us-county-choropleth.ts
index a8d2ac2ce6..73dfb256d6 100644
--- a/test/plots/us-county-choropleth.ts
+++ b/test/plots/us-county-choropleth.ts
@@ -23,7 +23,7 @@ export async function usCountyChoropleth() {
       label: "Unemployment (%)"
     },
     marks: [
-      Plot.geo(counties, {fill: (d) => unemployment.get(d.id), title: (d) => d.properties.name}),
+      Plot.geo(counties, {fill: (d) => unemployment.get(d.id), title: "name"}),
       Plot.geo(statemesh, {stroke: "white"})
     ]
   });

From 58b9182a56344a8b014583a3361469bf12dbac31 Mon Sep 17 00:00:00 2001
From: Mike Bostock <mbostock@gmail.com>
Date: Sun, 16 Jun 2024 09:39:00 -0700
Subject: [PATCH 2/2] use GeoJSON collections

---
 docs/marks/geo.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/marks/geo.md b/docs/marks/geo.md
index 895accc15f..eeea8d1875 100644
--- a/docs/marks/geo.md
+++ b/docs/marks/geo.md
@@ -11,8 +11,8 @@ const walmarts = shallowRef({type: "FeatureCollection", features: []});
 const world = shallowRef(null);
 const statemesh = computed(() => us.value ? topojson.mesh(us.value, us.value.objects.states, (a, b) => a !== b) : {type: null});
 const nation = computed(() => us.value ? topojson.feature(us.value, us.value.objects.nation) : {type: null});
-const states = computed(() => us.value ? topojson.feature(us.value, us.value.objects.states).features : []);
-const counties = computed(() => us.value ? topojson.feature(us.value, us.value.objects.counties).features : []);
+const states = computed(() => us.value ? topojson.feature(us.value, us.value.objects.states) : {type: null});
+const counties = computed(() => us.value ? topojson.feature(us.value, us.value.objects.counties) : {type: null});
 const land = computed(() => world.value ? topojson.feature(world.value, world.value.objects.land) : {type: null});
 
 onMounted(() => {