How to update parent record based on child records’ value

<div id="TreeGridContainer" style="height:400px;width:100%"></div>    
<script type="text/javascript">
$(function () {
$("#TreeGridContainer").ejTreeGrid({
//...
dataSource: projectData,
rowDataBound: rowDataBound,
actionComplete: actionComplete,
endEdit:endEdit, 
})
});
function rowDataBound(args) {
//Updating the parent record’s duration and end date in initial load and in adding action
var currentRecord = args.data,
parentItem = currentRecord.parentItem,
childRecords = parentItem && parentItem.childRecords;
if (parentItem && childRecords.indexOf(currentRecord) == childRecords.length - 1 && currentRecord.hasChildRecords === false) {
update(parentItem);
}
}
function actionComplete(args) {
// Updating the parent record’s duration and end date in delete action
if (args.requestType == "delete") {
var parentItem = args.data.parentItem;
var temp = update(parentItem);
}
// Updating the parent record’s duration and end date while adding a record
if (args.requestType == "addNewRow"&& args.previousValue) {
var parentItem = args.model.selectedItem.parentItem;
var temp = update(parentItem);
}
 
}
function endEdit(args) {
// Updating the parent record’s duration and end date after Editing            
var parentItem = args.model.selectedItem.parentItem;
var temp = update(parentItem);
}
function update(parentItem) {
 
var duration_count = 0, progress_count = 0;
if (parentItem != null) {
var endDate = [],
startDate=[],
childRecords = parentItem.childRecords,
len = childRecords.length,
startDate_maxObj = new Date(parentItem.childRecords[0].startDate),
startDate_max = parentItem.childRecords[0].startDate;
endDate_maxObj = new Date(parentItem.childRecords[0].endDate),
endDate_max = parentItem.childRecords[0].endDate;
 
for (var i = 0; i < len; i++) {
//To calculate the maximum end date among child records
if (new Date(parentItem.childRecords[i].endDate) > endDate_maxObj)                   
{ 
endDate_max = parentItem.childRecords[i].endDate;
endDate_maxObj = new Date(parentItem.childRecords[i].endDate);
}
//To calculate the maximum start date among child records
if (new Date(parentItem.childRecords[i].startDate) > startDate_maxObj) {
startDate_max = parentItem.childRecords[i].startDate;
startDate_maxObj = new Date(parentItem.childRecords[i].startDate);
}
//To update the duration and progress of the Parent Item
var duration = parentItem.childRecords[i].duration,
progress = parentItem.childRecords[i].progress;
if (duration)
duration_count = duration_count + parseInt(duration);
if (progress)
progress_count = progress_count + parseInt(progress);
parentItem.duration = duration_count.toString();
parentItem.progress = progress_count;
}
parentItem.endDate = endDate_max;
parentItem.startDate = startDate_max;
var obj = $("#TreeGridContainer").data("ejTreeGrid");
obj.refreshRow(obj.model.updatedRecords.indexOf(parentItem));
return update(parentItem.parentItem);
}
}
</script>