Google Apps script to list all subfolders and filenames inside of a given Google Drive folder

gistfile1.txt

function listFilesInFolder() {
  var folderName = "your folder name here"; // Replace with the name of your folder
  var folderId = "xyxyxyxyxyxyxyxyxyxyxyxyx-xyxyxyx (Replace everything in quotes here with string at end of folder URL)";
  var folder = DriveApp.getFolderById(folderId);

  if (folder) {
    var output = [];
    listFiles(folder, output);

    var doc = DocumentApp.create('Folder Contents - ' + folderName);
    doc.getBody().setText(output.join('\n'));
  } else {
    Logger.log("Folder not found: " + folderName);
  }
}

function listFiles(folder, output, indent) {
  if (!indent) {
    indent = '';
  }
  
  var files = folder.getFiles();
  while (files.hasNext()) {
    var file = files.next();
    output.push(indent + file.getName());
  }
  
  var subFolders = folder.getFolders();
  while (subFolders.hasNext()) {
    var subFolder = subFolders.next();
    output.push(indent + subFolder.getName() + '/');
    listFiles(subFolder, output, indent + '  ');
  }
}