Autofill google forms based on user input - google-apps-script

Question

Alright stack friends,
I'm working on my first projects using google scripts and it's been pretty fun so far. My project is to create a form for data entry that can either accept an ID number and fill in the rest of the fields, or let the user fill out the entire form. Basically my method to fill in the other fields is just to have a lookup table on the second sheet. When the user submits a form, the script runs, looks for the ID of the last row, scans the reference table for the ID, and then fills in the details.
I think the problem I'm having is the assumption that the data from the form is already in the sheet when the script runs. The problem I noticed is that the script sometimes fails to fill in the gaps. I tried creating form submissions in a loop with the same ID and they function somewhat erratically but it seems like the last sumbission always works which would make sense if the script executions are not matching up with the form submissions. Here's the script for reference:
function fillGaps() {
// First take in the appropriate spreadsheet objects and get the sheets from it
var ss = SpreadsheetApp.openById(id);
var sheet = ss.getSheets()[0];
var refSheet = ss.getSheets()[1];
// Here's the last rows' index
var lastRow = sheet.getLastRow();
var lastRowRef = refSheet.getLastRow();
// now this is an array of values for the last row and the student ID entered
var response = sheet.getRange(lastRow, 1, 1, 7).getValues();
var enteredID = response[0][1];
// Next we're going to try to load up the lookup table and scan for the ID
var stuIDs = refSheet.getRange(2, 4, refSheet.getLastRow()).getValues();
var row = 0;
while(enteredID != stuIDs[row] && row <= lastRowRef){
row++;
}
// Okay at this point the row variable is actually -2 from what the sheet index
// is that I'm thinking of. This is because we didn't load the first row (names)
// and the way arrays are indexed starts with 0.
row++;
row++;
// now assuming that it found a match we'll fill in the values
if(row < refSheet.getLastRow()){
// Alright now we need to wrangle that row and format the data
var matchedRow = refSheet.getRange(row, 1, 1, 6).getValues();
// modify the response
var replacement = [response[0][0],enteredID, matchedRow[0][1],matchedRow[0][0],matchedRow[0][2],matchedRow[0][4],matchedRow[0][5]];
sheet.getRange(lastRow, 1, 1, 7).setValues([replacement]) ;
}
}
So I'm wondering:
Does this seem like the right diagnosis?
If so, what would be the best way to remedy? I thought of adding a little delay into the script as well as trying to capture the submissions timestamp (not sure how to do that)
Thank you much!

Answer 1

The following code gives a 2D array:
var stuIDs = refSheet.getRange(2, 4, refSheet.getLastRow()).getValues();
Also,refSheet.getLastRow gives the last row, lets say it is 10 in this case. The syntax for getRange is getRange(row, column, numRows) and the last argument is the number of rows, not the last column. So in the above code the selected range would be row 2 - 11 rather than 2- 10. Unless that is what you intended, modify the code like so:
var stuIDs = refSheet.getRange(2, 4, refSheet.getLastRow()-1).getValues();
To access the values in stuIDs you should use stuIDs[row][0] (2D array) to check for matching ID. Assuming your ID was to be matched was in column 1.
Secondly, in the loop you are using the following to check for the last index in array row <= lastRowRef which will cause it go out of range(because array starts at 0 and sheet row at 1) instead use this row < stuIDs.length
Finally, in case you don't find a match you will end up with the last row and your code will end you taking the last row as the matched index. This can be prevented by using a boolean variable to check for a match.
var foundId = false
var row = 0;
var i = 0;
for (i in stuIDs){
if(stuIDs[i][0] == enteredID)
foundID = true
break
}
}
row = i + 2
if (foundID){
var matchedRow = refSheet.getRange(row, 1, 1, 6).getValues();
// modify the response
var replacement = [response[0][0],enteredID, matchedRow[0][1],matchedRow[0][0],matchedRow[0][2],matchedRow[0][4],matchedRow[0][5]];
sheet.getRange(lastRow, 1, 1, 7).setValues([replacement]) ;
}
PS: You can also use event objects to get the values of response (eventObj.values). As mentioned here: https://developers.google.com/apps-script/guides/triggers/events
Hope that helps!