From 3f37b4206cabd27aef97bc3b3d5060040a49ff5c Mon Sep 17 00:00:00 2001
From: Maksym Tsymbarov <mtsymbarov@thingsboard.io>
Date: Thu, 18 Dec 2025 17:42:28 +0200
Subject: [PATCH] Added normalization of y-axis limit in chart initialization

---
 .../widget/lib/chart/time-series-chart.ts     | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/chart/time-series-chart.ts b/ui-ngx/src/app/modules/home/components/widget/lib/chart/time-series-chart.ts
index 8568e4b13b..f52bf13ada 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/chart/time-series-chart.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/chart/time-series-chart.ts
@@ -581,6 +581,8 @@ export class TbTimeSeriesChart {
     yAxisSettingsList.sort((a1, a2) => a1.order - a2.order);
     const axisLimitDatasources: Datasource[] = [];
     for (const yAxisSettings of yAxisSettingsList) {
+      yAxisSettings.min = this.normalizeAxisLimit(yAxisSettings.min);
+      yAxisSettings.max = this.normalizeAxisLimit(yAxisSettings.max);
       const axisSettings = mergeDeep<TimeSeriesChartYAxisSettings>({} as TimeSeriesChartYAxisSettings,
         defaultTimeSeriesChartYAxisSettings, yAxisSettings);
       const units = isNotEmptyTbUnits(axisSettings.units) ? axisSettings.units : this.ctx.units;
@@ -1078,4 +1080,21 @@ export class TbTimeSeriesChart {
       this.timeSeriesChart.setOption(this.timeSeriesChartOptions);
     }
   }
+
+  private normalizeAxisLimit(limit: string | number | ValueSourceConfig): string | number | ValueSourceConfig  {
+    if (!limit) {
+      return {
+        type: ValueSourceType.constant,
+        value: null,
+        entityAlias: null
+      };
+    } else if (typeof limit === 'number' || typeof limit === 'string') {
+      return {
+        type: ValueSourceType.constant,
+        value: Number(limit),
+        entityAlias: null
+      };
+    }
+    return limit;
+  }
 }