added as const to help compiler

labs/lab7/src/chart/components/GroupChart.tsx

@@ -17,14 +17,14 @@ function GroupChart({ data }: GroupProps) {
         'Средняя высота': false,
         'Минимальная высота': false,
     });
-    let seriesY = Object.entries(series)
-        .filter(item => item[1] == true)
-        .map(item => {
-            return {
-                "dataKey": item[0], "label": item[0], barLabel: Object.entries(series)
-                    .filter(item => item[1] == true).length == 1 ? "value" : ""
-            }
-        });
+    const selectedSeries = Object.entries(series).filter(item => item[1] === true);
+    let seriesY = selectedSeries.map(item => {
+        return {
+            dataKey: item[0],
+            label: item[0],
+            barLabel: selectedSeries.length === 1 ? ('value' as const) : undefined,
+        }
+    });
     const chartSetting = {
         yAxis: [{ label: 'Высота (м)' }],
         height: 400,