perf: 优化折线图取值区间

@@ -43,6 +43,12 @@ const handleHistoryData = (message: SubscriptionData, attr: string) => {
   } as EChartsOption)
 }
 
+function sliceData(data: any[], maxLength = 20) {
+  if (data.length > maxLength)
+    return data.slice(1)
+  return data
+}
+
 const handlerTimeSeriesData = (message: SubscriptionData, attr: string) => {
   const { ts, latestValue } = useLatestMessageValue(message, attr)
   const option = unref(chartInstance)?.getOption() as EChartsOption
@@ -51,8 +57,8 @@ const handlerTimeSeriesData = (message: SubscriptionData, attr: string) => {
   xAxisData.push(formatToDateTime(ts))
   seriesData.push(latestValue)
   unref(chartInstance)?.setOption({
-    xAxis: { data: xAxisData },
-    series: { data: seriesData },
+    xAxis: { data: sliceData(xAxisData) },
+    series: { data: sliceData(seriesData) },
   } as EChartsOption)
 }