Appending and deleting row from a response sheet from older timestamp? - google-apps-script

Question

I am having a google response sheet. I run this sheet every night at 12. whenever some response are received I want to append the row to another sheet and delete the respective row in form responses. Here I want to start appending from the oldest timestamp in form responses i.e. from row number two as row number 1 is questions. whenever Irun this code, I am successfully appending the row but not able to delete the row.
Here is the code I am trying to do:
//** Copying the response to another Spreadsheet for roster management**//
function copySheet(){
var source = SpreadsheetApp.getActiveSpreadsheet();
var sourceSheet = source.getSheetByName("Form Responses 1");
var lastRow = sourceSheet.getLastRow();
var getData = sourceSheet.getDataRange().getValues();
var destSheet = source.getSheetByName("10017135ADC");
Logger.log(lastRow);
if(lastRow >1){
for (var j =1; j<lastRow; j++) {
// Logger.log(j);
var rowData = getData[j];
// Logger.log(rowData);
destSheet.appendRow(rowData);
sourceSheet.deleteRow(j);
}
}
}

Answer 1

Try this:
function copySheet(){
var source = SpreadsheetApp.getActiveSpreadsheet();
var sourceSheet = source.getSheetByName("Form Responses 1");
var lastRow = sourceSheet.getLastRow();
var getData = sourceSheet.getDataRange().getValues();
var destSheet = source.getSheetByName("10017135ADC");
Logger.log(lastRow);
let d=0;//keep track of deleted rows
if(lastRow >1){
for (var j =1; j<lastRow; j++) {
// Logger.log(j);
var rowData = getData[j];
// Logger.log(rowData);
destSheet.appendRow(rowData);
sourceSheet.deleteRow(j-d++);
}
}
}

Answer 2

Cooper's new variable approach was good. But upwards for deletion is a better approach.
Try something like this
for (var i = getData.length - 1; i > 1; i--) {
//anything you want to perform
destSheet.appendRow(getData[i]);
sheet.deleteRow(i);
}