How do I detect the newest row in a specific column? - google-apps-script

Question

I am currently having some problems with my Google App Script.
What we have for now is: when the users input two values(time) into the column, the duration between the column will be automatically calculated in another column, which we did this by the functions in the Spreadsheet itself.
When we transfer the input values, we are using the function appendRow, and since things will get messed up in the column we set the value that is supposed to go in the duration column as null, so that it will be filled blank and that the function in the Spreadsheet itself will calculate it. However, the problem we encountered was that by using this function in the Spreadsheet, we get a 00:00 as a default value in every single row that doesn't have a time input, meaning that the appendRow function will detect these rows as filled, and will append the values to the very bottom of the Spreadsheet, creating a big gap between the rows with the values and without the values.
We need a solution to solve this issue, and we are posting to get any possible solutions about this.
So the method we thought of to solve this issue was using getRange(), then setValue. With getRange we thought of using something like make a 1x1 grid that has the row Index as the same row Index as the new cell in the specific column that we want to import the values, and for columns we can just choose the column Index. But we soon realized that this will still fail as appendRow in the row Index will still return the row index of the very last row in the spreadsheet.
The next method we tried was to detect any "0:00:00" in the duration column, then get the corresponding row Index, and use that row Index to setValue at that specific row using getRange(), which again, failed.
for (var i = 0; i < sheet.getMaxRows()+1; i++ ){
if (sheet.getRange(i,4).getValue() === "0:00:00") {
sheet.getRange(i,1).setValue(datas.enterDate);
sheet.getRange(i,2).setValue(datas.enterStartTime);
sheet.getRange(i,3).setValue(datas.enterEndTime);
sheet.getRange(i,6).setValue(datas.enterFullName);
sheet.getRange(i,7).setValue(datas.enterCategory);
sheet.getRange(i,8).setValue(datas.enterActivity);
sheet.getRange(i,9).setValue(datas.enterLink);
break;
}
}
Expected results: As the function goes down the column it will search for any cells containing "0:00:00", and when it does it will set the values with the users data.
Output: Nothing shown.

Answer 1

Try this:
col is the column number. The default is the column of the active cell
sh is a Sheet Obj and the the default is current active sheet
ss is a Spreadsheet Object and the default is the current active spreadsheet.
function newestRow(col,sh,ss){
var ss=ss || SpreadsheetApp.getActive();
var sh=sh || ss.getActiveSheet();
var col=col || sh.getActiveCell().getColumn();
var rg=sh.getRange(1,col,sh.getLastRow(),1);
var vA=rg.getValues();
while(vA[vA.length-1][0].length==0){
vA.splice(vA.length-1,1);
}
return vA.length+1;
}