From c174664e636d885251dd1da659715e2b14b15f88 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Torkel=20=C3=96degaard?= <torkel@grafana.org>
Date: Tue, 19 Oct 2021 15:03:33 +0200
Subject: [PATCH] Scale: Fixes handling of NaN percent when data min = data max
 (#40622)

---
 packages/grafana-data/src/field/scale.test.ts | 16 +++++++++++++++-
 packages/grafana-data/src/field/scale.ts      |  4 ++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/packages/grafana-data/src/field/scale.test.ts b/packages/grafana-data/src/field/scale.test.ts
index 2e6924ffb8b..da8340a4bef 100644
--- a/packages/grafana-data/src/field/scale.test.ts
+++ b/packages/grafana-data/src/field/scale.test.ts
@@ -1,4 +1,4 @@
-import { ThresholdsMode, Field, FieldType } from '../types';
+import { ThresholdsMode, Field, FieldType, FieldColorModeId } from '../types';
 import { sortThresholds } from './thresholds';
 import { ArrayVector } from '../vector/ArrayVector';
 import { getScaleCalculator } from './scale';
@@ -49,4 +49,18 @@ describe('getScaleCalculator', () => {
       threshold: undefined,
     });
   });
+
+  it('should handle min = max', () => {
+    const field: Field = {
+      name: 'test',
+      config: { color: { mode: FieldColorModeId.ContinuousGrYlRd } },
+      type: FieldType.number,
+      values: new ArrayVector([1]),
+    };
+
+    const theme = createTheme();
+    const calc = getScaleCalculator(field, theme);
+
+    expect(calc(1).color).toEqual('rgb(115, 191, 105)');
+  });
 });
diff --git a/packages/grafana-data/src/field/scale.ts b/packages/grafana-data/src/field/scale.ts
index 51acd3af63f..f97277966a6 100644
--- a/packages/grafana-data/src/field/scale.ts
+++ b/packages/grafana-data/src/field/scale.ts
@@ -27,6 +27,10 @@ export function getScaleCalculator(field: Field, theme: GrafanaTheme2): ScaleCal
 
     if (value !== -Infinity) {
       percent = (value - info.min!) / info.delta;
+
+      if (Number.isNaN(percent)) {
+        percent = 0;
+      }
     }
 
     const threshold = getActiveThresholdForValue(field, value, percent);