From 9eece99629af920f7588c1a216f61698abf9edad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philippe=20Rivi=C3=A8re?= <fil@rezo.net>
Date: Wed, 16 Aug 2023 17:23:19 +0200
Subject: [PATCH 1/2] expose a deduplicated ordinal domain

closes #1812
---
 src/scales/ordinal.js      |  1 +
 test/scales/scales-test.js | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/scales/ordinal.js b/src/scales/ordinal.js
index 2e7dd0c0de..9cbbb62749 100644
--- a/src/scales/ordinal.js
+++ b/src/scales/ordinal.js
@@ -15,6 +15,7 @@ export const ordinalImplicit = Symbol("ordinal");
 function createScaleO(key, scale, channels, {type, interval, domain, range, reverse, hint}) {
   interval = maybeRangeInterval(interval, type);
   if (domain === undefined) domain = inferDomain(channels, interval, key);
+  domain = [...new InternSet(domain)];
   if (type === "categorical" || type === ordinalImplicit) type = "ordinal"; // shorthand for color schemes
   if (reverse) domain = reverseof(domain);
   scale.domain(domain);
diff --git a/test/scales/scales-test.js b/test/scales/scales-test.js
index 2303cfc2ef..146e0e1a92 100644
--- a/test/scales/scales-test.js
+++ b/test/scales/scales-test.js
@@ -2102,6 +2102,36 @@ it("plot(…).scale(name).apply and invert return the expected functions", () =>
   ]);
 });
 
+it("plot(…).scale(name) returns a deduplicated ordinal domain", () => {
+  const letters = "abbbcaabbcc";
+  const plot = Plot.dotX(letters).plot({x: {domain: letters}});
+  scaleEqual(plot.scale("x"), {
+    align: 0.5,
+    bandwidth: 0,
+    domain: ["a", "b", "c"],
+    padding: 0.5,
+    range: [20, 620],
+    round: true,
+    step: 200,
+    type: "point"
+  });
+});
+
+it("plot(…).scale(name) returns a deduplicated ordinal/temporal domain", () => {
+  const dates = ["2001", "2002", "2004", "2004"].map(d3.isoParse);
+  const plot = Plot.dotX(dates).plot({x: {type: "point", domain: dates}});
+  scaleEqual(plot.scale("x"), {
+    align: 0.5,
+    bandwidth: 0,
+    domain: dates.slice(0, 3),
+    padding: 0.5,
+    range: [20, 620],
+    round: true,
+    step: 200,
+    type: "point"
+  });
+});
+
 // Given a plot specification (or, as shorthand, an array of marks or a single
 // mark), asserts that the given named scales, when materialized from the first
 // plot and used to produce a second plot, produce the same output and the same

From ed1f30af02027430c380abb2b3fccb2958e35ced Mon Sep 17 00:00:00 2001
From: Mike Bostock <mbostock@gmail.com>
Date: Wed, 16 Aug 2023 08:49:07 -0700
Subject: [PATCH 2/2] =?UTF-8?q?use=20scale=E2=80=99s=20deduplicated=20doma?=
 =?UTF-8?q?in?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/scales/ordinal.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/scales/ordinal.js b/src/scales/ordinal.js
index 9cbbb62749..caf18a4e13 100644
--- a/src/scales/ordinal.js
+++ b/src/scales/ordinal.js
@@ -15,10 +15,9 @@ export const ordinalImplicit = Symbol("ordinal");
 function createScaleO(key, scale, channels, {type, interval, domain, range, reverse, hint}) {
   interval = maybeRangeInterval(interval, type);
   if (domain === undefined) domain = inferDomain(channels, interval, key);
-  domain = [...new InternSet(domain)];
   if (type === "categorical" || type === ordinalImplicit) type = "ordinal"; // shorthand for color schemes
   if (reverse) domain = reverseof(domain);
-  scale.domain(domain);
+  domain = scale.domain(domain).domain(); // deduplicate
   if (range !== undefined) {
     // If the range is specified as a function, pass it the domain.
     if (typeof range === "function") range = range(domain);