Generate a tree view of Google Shared Drives in Markdown format

(Sample) Map of Shared Drive.md

[This is sample output of the above script for a shared drive named "Shared Drive"]

Shared Drive

Number of files in root of Shared drive: 4

• Folder 1
  • Folder 1a (12 files)
  • Folder 1b (13 files)
• Folder 2 (1 files)
• Folder 3 (3 files)
  • Folder 3a (12 files)
  • Folder 3b (9 files)
  • Folder 3c (15 files)
  • Folder 3d (6 files)

sharedDriveTrees.gs

/**
 * Generate trees for all (if less than 100) Shared Drives in the domain (requires domain admin permissions)
 */
function generateSharedDriveTrees() {
  // Get (first 100) Shared Drives for domain
  const drives = Drive.Drives.list({useDomainAdminAccess: true, maxResults: 100}).items;
  drives.forEach(drive => generateSharedDriveTree(drive));
}

/**
 * Lists Shared Drive name, URL and file count then generates tree for all children (if permissions allow)
 * @param {Drives} drive The [drives Resource](https://developers.google.com/drive/api/v3/reference/drives#resource) to iterate
 */
function generateSharedDriveTree(drive) {
  try {
    var result = [];

    const query = "trashed = false and '" + drive.id + "' in parents and mimeType != 'application/vnd.google-apps.folder'";
    const filesInFolder = Drive.Files.list({q: query, includeItemsFromAllDrives: true, supportsAllDrives: true});
    
    result.push("# [" + drive.name + "](https://drive.google.com/drive/folders/" + drive.id + ")" + "\n");
    if (filesInFolder.items.length > 0) {
      result.push("Number of files in root of Shared drive: " + filesInFolder.items.length + "\n");
     } else {
       result.push("*If this file is empty you may not have permission to view the contents of this Shared Drive*\n")
     }

    getChildFolders(result, drive.id); // use getChildFolders(result, drive.id, 1, 5) to override maxDepth to 5

    outputFile = DriveApp.createFile('Map of ' + drive.name + '.md', result.join("\n"));
    DriveApp.addFile(outputFile);
  } catch (e) {
    Logger.log(e.toString());
  }
}

/**
 * Recursively lists folder names, URLs and file counts
 * @param {array}  result       Result array to populate
 * @param {string} parent       Parent folder ID
 * @param {number} currentDepth Current depth of tree, defaults to 1, must be between 1 and maxDepth inclusive
 * @param {number} maxDepth     Maximum depth of tree, defaults to 3, must be between 1 and 10
 */
function getChildFolders(result, parent, currentDepth = 1, maxDepth = 3) {
  if (currentDepth > maxDepth || currentDepth < 1 || maxDepth < 1 || maxDepth > 10) {
    return result;
  }

  const folderQuery = "trashed = false and '" + parent + "' in parents and mimeType = 'application/vnd.google-apps.folder'";
  const childFolders = Drive.Files.list({q: folderQuery, includeItemsFromAllDrives: true, supportsAllDrives: true}).items;

  for (const childFolder of childFolders) {
    const fileQuery = "trashed = false and '" + childFolder.getId() + "' in parents and mimeType != 'application/vnd.google-apps.folder'";
    const filesInFolder = Drive.Files.list({q: fileQuery, includeItemsFromAllDrives: true, supportsAllDrives: true});
    const countString = filesInFolder.items.length > 0 ? " (" + filesInFolder.items.length + " files)" : ""

    result.push("\t".repeat(currentDepth - 1) + "- [" + childFolder.title + "](" + childFolder.alternateLink + ")" + countString);

    // Recursive call for any sub-folders (unless we've already reached maxDepth)
    if (currentDepth < maxDepth) {
      getChildFolders(result, childFolder.id, currentDepth + 1, maxDepth);
    }
  }
}