New function: get values of current options

Returns the values of the currently selected options in the linked
drop down lists

public/js/dropDownList.js

@@ -144,3 +144,17 @@ document
 // These functions run after "DOMContentLoaded" event
 populateFirstLevelDropDown();
 applyDropDown();
+
+/**
+ * Get the values from the currently selected options in the linked drop dpwn lists
+ * @returns {Array} An array containing the values of the selected options
+ */
+const getSelectedOptionsFromDropDownLists = function () {
+  const selectedBuilding = document.querySelector("#drop-down--bldg").value;
+  const selectedSensor = document.querySelector("#drop-down--sensor").value;
+  const selectedSamplingRate = document.querySelector(
+    "#drop-down--sampling-rate"
+  ).value;
+
+  return [selectedBuilding, selectedSensor, selectedSamplingRate];
+};