How to avoid creating duplicate folders in Google Drive - google-sheets

Question

function saveAsCSV() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheets = ss.getSheets();
// create a folder from the name of the spreadsheet
var folder = DriveApp.createFolder(ss.getName().toLowerCase().replace(/ /g,'_') + '_csv');
for (var i = 0 ; i < sheets.length ; i++) {
var sheet = sheets[i];
// append ".csv" extension to the sheet name
fileName = sheet.getName() + ".csv";
// convert all available sheet data to csv format
var csvFile = convertRangeToCsvFile_(fileName, sheet);
// create a file in the Docs List with the given name and the csv data
folder.createFile(fileName, csvFile);
}
}
This code creates CSV file from a spreadsheet by creating a folder with the spreadsheet's name with 'CSV' added to it. I have been unable to stop it from making a new folder each time, as I want the csv file to be placed in this specific folder each time to update the data. I know I need to see if the folder exists and if not, create it first, otherwise just put the csv file in the existing folder (or the one that was created). It sounds simple, but I have been unable to do it.

Answer 1

You could create a helper function that checks if the folder exists. If it exists the function can return the folder, if it doesn't it can create the folder. In both cases, it will return a folder object.
function yourFunction() {
/*
some code
....
*/
//Get the folder by calling the helper function.
var folder = getFolder("nameOfFolder");
//Create a file in the folder
folder.createFile("fileName", csvFile)
/*
some more code
....
*/
}
//Returns the folder or creates it if it doesn't exist.
function getFolder(folderName) {
var f = DriveApp.getFoldersByName(folderName);
return f.hasNext() ? f.next() : DriveApp.createFolder(folderName);
}

Answer 2

Test out the function below with a try{} catch(e){} to either find or create the folder.
NOTE: this function checks every folder on your drive, so if you have a large number of folders you may need to modify it to only check within a folder.
function testFolder(folderName){
var exist = false;
for(var i in targetFolders){
var parentFolder = DriveApp.getFolderById(targetFolders[i]);
var childFolders = parentFolder.getFolders();
while(childFolders.hasNext()) {
var child = childFolders.next();
Logger.log('listFolders ' + child.getName());
if(child.getName() == folderName){
exist=true;
break;
}
}
}
return exist;
}