diff --git a/public/js/appChart.js b/public/js/appChart.js
index 7e4047912e90616217ea8c1945d8709cf9b7bfa4..f1a1d08b8f1aae01a0b9b239fa1ce0b31f4252d8 100644
--- a/public/js/appChart.js
+++ b/public/js/appChart.js
@@ -19,36 +19,37 @@ const PARAM_FILTER2 =
   "resultTime ge 2020-06-01T00:00:00.000Z and resultTime le 2021-01-01T00:00:00.000Z";
 
 /**
- * Draw a heatmap using Highcharts library
+ * Format the response from SensorThings API to make it suitable for heatmap
  * @param {*} obsArray - Response from SensorThings API as array
+ * @returns {Array}
+ */
+const formatSTAResponseForHeatMap = function (obsArray) {
+  const dataSTAFormatted = [];
+  obsArray.forEach((obs) => {
+    // Get the date/time string; first element in input array; remove trailing "Z"
+    const obsDateTimeInput = obs[0].slice(0, -1);
+    // Get the "date" part of an observation
+    const obsDateInput = obs[0].slice(0, 10);
+    // Create Date objects
+    const obsDateTime = new Date(obsDateTimeInput);
+    const obsDate = new Date(obsDateInput);
+    // x-axis -> timestamp; will be the same for observations from the same date
+    const timestamp = Date.parse(obsDate);
+    // y-axis -> hourOfDay
+    const hourOfDay = obsDateTime.getHours();
+    // value -> the observation's value; second element in input array
+    const value = obs[1];
+    dataSTAFormatted.push([timestamp, hourOfDay, value]);
+  });
+  return dataSTAFormatted;
+};
+
+/**
+ * Draw a heatmap using Highcharts library
+ * @param {*} obsArray - Response from SensorThings API
  * @returns {void}
  */
 const drawHeatMapHC = function (obsArray) {
-  /**
-   * Format the response from SensorThings API to make it suitable for heatmap
-   * @returns {Array}
-   */
-  const formatSTAResponseForHeatMap = function () {
-    const dataSTAFormatted = [];
-    obsArray.forEach((obs) => {
-      // Get the date/time string; first element in input array; remove trailing "Z"
-      const obsDateTimeInput = obs[0].slice(0, -1);
-      // Get the "date" part of an observation
-      const obsDateInput = obs[0].slice(0, 10);
-      // Create Date objects
-      const obsDateTime = new Date(obsDateTimeInput);
-      const obsDate = new Date(obsDateInput);
-      // x-axis -> timestamp; will be the same for observations from the same date
-      const timestamp = Date.parse(obsDate);
-      // y-axis -> hourOfDay
-      const hourOfDay = obsDateTime.getHours();
-      // value -> the observation's value; second element in input array
-      const value = obs[1];
-      dataSTAFormatted.push([timestamp, hourOfDay, value]);
-    });
-    return dataSTAFormatted;
-  };
-
   Highcharts.chart("chart-heatmap", {
     chart: {
       type: "heatmap",
@@ -122,7 +123,7 @@ const drawHeatMapHC = function (obsArray) {
 
     series: [
       {
-        data: formatSTAResponseForHeatMap(),
+        data: formatSTAResponseForHeatMap(obsArray),
         boostThreshold: 100,
         borderWidth: 0,
         nullColor: "#525252",
@@ -200,6 +201,5 @@ followNextLink(
     console.log(err);
   })
   .then((observationArr) => {
-    // drawHeatMapAC2(observationArr);
     drawHeatMapHC(observationArr);
   });