From dc72f7ed97fed874bd3ac264ea0c385043efa313 Mon Sep 17 00:00:00 2001
From: Steve Dignam <sbdchd@users.noreply.github.com>
Date: Mon, 3 Feb 2020 12:03:32 -0500
Subject: [PATCH] chart.js: Update ChartData to accept both Arrays and
 ReadonlyArrays (#42023)

By changing the types for `ChartData["labels"]` and `ChartData["datasets"]`
to ReadonlyArrays we can pass either ReadonlyArrays or Arrays as ChartData.

This is useful when chart.js is used inside a React component where the
props are readonly.
---
 types/chart.js/chart.js-tests.ts | 9 +++++++++
 types/chart.js/index.d.ts        | 4 ++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/types/chart.js/chart.js-tests.ts b/types/chart.js/chart.js-tests.ts
index 3f391ddd5a..8d82393822 100644
--- a/types/chart.js/chart.js-tests.ts
+++ b/types/chart.js/chart.js-tests.ts
@@ -411,6 +411,15 @@ if (doughnutChart.getDatasetMeta(0).data.length > 0) {
     console.log(doughnutChartView.y);
 }
 
+// Passing readonly data as ChartData
+const readonlyDataInput: {
+    labels: ReadonlyArray<string>;
+    datasets: ReadonlyArray<{
+        data: number[];
+    }>;
+} = { labels: [], datasets: [] };
+const readonlyData: Chart.ChartData = readonlyDataInput;
+
 // Time Cartesian Axis
 const timeAxisChartData: Chart.ChartData = {
     datasets: [{
diff --git a/types/chart.js/index.d.ts b/types/chart.js/index.d.ts
index d40d1d8c23..17698d362a 100644
--- a/types/chart.js/index.d.ts
+++ b/types/chart.js/index.d.ts
@@ -243,8 +243,8 @@ declare namespace Chart {
     }
 
     interface ChartData {
-        labels?: Array<string | string[] | number | number[] | Date | Date[] | Moment | Moment[]>;
-        datasets?: ChartDataSets[];
+        labels?: ReadonlyArray<string | ReadonlyArray<string> | number | ReadonlyArray<number> | Date | ReadonlyArray<Date> | Moment | ReadonlyArray<Moment>>;
+        datasets?: ReadonlyArray<ChartDataSets>;
     }
 
     interface RadialChartOptions extends ChartOptions {