DriveApp.getFolders() not working as expected - google-apps-script

Question

I have a Google Apps Script for Sheets (running as a script under Sheets) that is supposed to return all the folders in my Google drive, however, the following code is stuck in an endless loop and only shows 1 of 3 folders in the drive - over and over again.
//this doesn't work -only shows 1 folder and repeats indefinitely
function getMyFolders() {
var f;
while (DriveApp.getFolders().hasNext()) {
f = DriveApp.getFolders().next();
console.log("f: " +f.getName());
}
}
The code returns the name of only one of my folders (hasNext() is clearly not working or there is a bug in Google Apps Scripts - since the while condition is never false (I ran it for several minutes and it never stopped!)
Could this be a security issue? This is just one of the problems I've run into. The other is that the 3 folders are subfolders of the same parent folder. No sure why getFolders() is not returning just the parent (that would make more sense).

Answer 1

Get All My Files
function getAllMyFiles(folder=DriveApp.getRootFolder()) {
const ss = SpreadsheetApp.getActive();
const sh = ss.getSheetByName('Sheet0');
let files = folder.getFiles();
while(files.hasNext()) {
let file = files.next()
sh.appendRow([file.getName(),file.getId()]);
}
let sfldrs = folder.getFolders();
while(sfldrs.hasNext()) {
let sfldr = sfldrs.next();
getAllMyFiles(sfldr)
}
}

Answer 2

Try this as your function instead to return just the parent folders!
function getMyFolders() {
let folders = DriveApp.getFolders();
while (folders.hasNext()) {
console.log("f: " +folders.next().getName());
}
}
If you want child folders as well, you would need to use recursion. Are you familiar with the concept? Happy to update my answer with that information if it's helpful.
Explanation:
You were calling DriveApp.getFolders(); on every iteration, so hasNext() was always retrieving the same item (the first folder in the iterator). Hence, you had an infinite loop.

Answer 3

I rewrote Cooper's answer to get all folders underneath a given parent.
In my case the parent folder is called "Gill".
function getAllMyFolders(folder=DriveApp.getFoldersByName("Gill").next()) {
let sfldrs = folder.getFolders();
while(sfldrs.hasNext()) {
let sfldr = sfldrs.next();
console.log("folder name: " +sfldr.getName());
getAllMyFolders(sfldr)
}
}
Ok - I played around with this code and discovered recursion is completely unnecessary, so here's code that will return all folders at all levels, then you can test the level with getParents()
function getMyFolders() {
let folders = DriveApp.getFolders();
while (folders.hasNext()) {
let folder = folders.next();
Logger.log(folder.getName() + ", Parent Folder: " + folder.getParents().next().getName());
}
}
I had a hunch that using a recursive function was the wrong way to go (and it looks terrible plus adds unnecessary overhead) but was confused why, my first attempt in this question did not work. The answer was the way my code was written - apparently, you need to assign DriveApp.getFolders() to a variable only once. Simply putting it in more than once, seems to reset it. That is, checking for DriveApp.getFolders().hasNext() and followed by DriveApp.getFolders().next() will cause the endless loop! Lesson here: assign it to a variable and then check for hasNext as calling it changes the state of the iterator which is reset again if getFolders is called again.
That was my actual bug here.