list all files google drive folder

app.gs

// Based on https://stackoverflow.com/a/36277049/1248256

// TODO: Set folder ID
var folderId = '';

// Main function 1: List all folders, & write into the current sheet.
function listFolers(){
  getFolderTree(folderId, false);
};

// Main function 2: List all files & folders, & write into the current sheet.
function listAll(){
  getFolderTree(folderId, true); 
};

// =================
// Get Folder Tree
function getFolderTree(folderId, listAll) {
  try {
    // Get folder by id
    var parentFolder = DriveApp.getFolderById(folderId);

    // Initialise the sheet
    var file, data, sheet = SpreadsheetApp.getActiveSheet();
    sheet.clear();
    sheet.appendRow(["Full Path", "Name", "Date", "URL", "Last Updated", "Description", "Size"]);

    getFiles(parentFolder, '', sheet, listAll)
    
    // Get files and folders
    getChildFolders(parentFolder.getName(), parentFolder, data, sheet, listAll);

  } catch (e) {
    Logger.log(e.toString());
  }
};

// List files inside the folder
function getFiles(folder, parentName, sheet, listAll) {
  // List files inside the folder
    var files = folder.getFiles();
    while (listAll & files.hasNext()) {
      var childFile = files.next();
      // Logger.log("File Name: " + childFile.getName());
      data = [ 
        parentName + "/" + folder.getName() + "/" + childFile.getName(),
        childFile.getName(),
        childFile.getDateCreated(),
        childFile.getUrl(),
        childFile.getLastUpdated(),
        childFile.getDescription(),
        childFile.getSize()
      ];
      // Write
      sheet.appendRow(data);
    }
}

// Get the list of files and folders and their metadata in recursive mode
function getChildFolders(parentName, parent, data, sheet, listAll) {
  var childFolders = parent.getFolders();

  // List folders inside the folder
  while (childFolders.hasNext()) {
    var childFolder = childFolders.next();
    // Logger.log("Folder Name: " + childFolder.getName());
    data = [ 
      parentName + "/" + childFolder.getName(),
      childFolder.getName(),
      childFolder.getDateCreated(),
      childFolder.getUrl(),
      childFolder.getLastUpdated(),
      childFolder.getDescription(),
      childFolder.getSize()
    ];
    // Write
    sheet.appendRow(data);

    getFiles(childFolder, parentName, sheet, listAll)

    // Recursive call of the subfolder
    getChildFolders(parentName + "/" + childFolder.getName(), childFolder, data, sheet, listAll);  
  }
};