groupBy(): minor refactor

dist/datasource-zabbix/timeseries.js

@@ -83,6 +83,10 @@ System.register(['lodash', './utils'], function (_export, _context) {
   }
 
   function groupBy_perf(datapoints, interval, groupByCallback) {
+    if (datapoints.length === 0) {
+      return [];
+    }
+
     var ms_interval = utils.parseInterval(interval);
     var grouped_series = [];
     var frame_values = [];

dist/test/datasource-zabbix/timeseries.js

@@ -108,6 +108,10 @@ function groupBy(datapoints, interval, groupByCallback) {
 }
 
 function groupBy_perf(datapoints, interval, groupByCallback) {
+  if (datapoints.length === 0) {
+    return [];
+  }
+
   var ms_interval = utils.parseInterval(interval);
   var grouped_series = [];
   var frame_values = [];

src/datasource-zabbix/timeseries.js

@@ -95,6 +95,10 @@ function groupBy(datapoints, interval, groupByCallback) {
 }
 
 function groupBy_perf(datapoints, interval, groupByCallback) {
+  if (datapoints.length === 0) {
+    return [];
+  }
+
   let ms_interval = utils.parseInterval(interval);
   let grouped_series = [];
   let frame_values = [];
@@ -103,32 +107,28 @@ function groupBy_perf(datapoints, interval, groupByCallback) {
   let point_frame_ts = frame_ts;
   let point;
 
-  if (datapoints.length > 0) {
+  for (let i=0; i < datapoints.length; i++) {
+    point = datapoints[i];
+    point_frame_ts = getPointTimeFrame(point[POINT_TIMESTAMP], ms_interval);
+    if (point_frame_ts === frame_ts) {
+      frame_values.push(point[POINT_VALUE]);
+    } else if (point_frame_ts > frame_ts) {
+      frame_value = groupByCallback(frame_values);
+      grouped_series.push([frame_value, frame_ts]);
 
-    for (let i=0; i < datapoints.length; i++) {
+      // Move frame window to next non-empty interval and fill empty by null
-      point = datapoints[i];
+      frame_ts += ms_interval;
-      point_frame_ts = getPointTimeFrame(point[POINT_TIMESTAMP], ms_interval);
+      while (frame_ts < point_frame_ts) {
-      if (point_frame_ts === frame_ts) {
+        grouped_series.push([null, frame_ts]);
-        frame_values.push(point[POINT_VALUE]);
-      } else if (point_frame_ts > frame_ts) {
-        frame_value = groupByCallback(frame_values);
-        grouped_series.push([frame_value, frame_ts]);
-
-        // Move frame window to next non-empty interval and fill empty by null
         frame_ts += ms_interval;
-        while (frame_ts < point_frame_ts) {
-          grouped_series.push([null, frame_ts]);
-          frame_ts += ms_interval;
-        }
-        frame_values = [point[POINT_VALUE]];
       }
+      frame_values = [point[POINT_VALUE]];
     }
-
-    frame_value = groupByCallback(frame_values);
-    grouped_series.push([frame_value, frame_ts]);
-
   }
 
+  frame_value = groupByCallback(frame_values);
+  grouped_series.push([frame_value, frame_ts]);
+
   return grouped_series;
 }