From 5d5871fb63f065ae497a9a9da4011b276ba884e1 Mon Sep 17 00:00:00 2001
From: Jerad Meisner <jerad.meisner@gmail.com>
Date: Tue, 9 Oct 2018 02:12:04 -0700
Subject: [PATCH] Fix error when only one state history entry. (#1750)

---
 src/panels/lovelace/cards/hui-sensor-card.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/panels/lovelace/cards/hui-sensor-card.js b/src/panels/lovelace/cards/hui-sensor-card.js
index fe03fedd2de1..21f64f5760fe 100644
--- a/src/panels/lovelace/cards/hui-sensor-card.js
+++ b/src/panels/lovelace/cards/hui-sensor-card.js
@@ -120,6 +120,8 @@ class HuiSensorCard extends EventsMixin(LitElement) {
     const min = Math.floor(Math.min.apply(null, values) * 0.95);
     const max = Math.ceil(Math.max.apply(null, values) * 1.05);
 
+    if (values.length === 1) values.push(values[0]);
+
     const yRatio = (max - min) / height;
     const xRatio = width / (values.length - 1);