list-files-in-folder.gs

function test_listFilesInFolder() {
  listFilesInFolder("StackOverflow");
}


/**
 * @OnlyCurrentDoc  Limits the script to only accessing the current spreadsheet.
 */

function onOpen() {
  var ui = SpreadsheetApp.getUi();
  ui.createMenu('Custom Menu')
      .addItem('List folder files', 'listFilesInFolder')
      .addToUi();
}


/**
 * List all files in Google Drive folder.
 *
 * @param {string} folderName    (optional) Name of folder on Google Drive
 *
 * Adapted from:
 * http://ctrlq.org/code/19854-list-files-in-google-drive-folder
 * https://gist.github.com/hubgit/3755293
 */
function listFilesInFolder(folderName) {
  // If we have not been provided a folderName, assume we will interact with user.
  var interactive = (typeof folderName === 'undefined');
  
  // Get name of folder to list
  if (interactive) {
    folderName = Browser.inputBox("List files in folder", "Enter folder name", Browser.Buttons.OK_CANCEL);
  }
  
  if (folderName === '') return;  // No name provided, exit quietly

  Logger.log(folderName);
  var folders = DriveApp.getFoldersByName(folderName);
  if (!folders.hasNext()) {
    if (interactive) Browser.msgBox("Folder not found.");
    return;
  }
  var folder = folders.next();
  var contents = folder.getFiles();

  // Find or add sheet with folder name
  var ss = SpreadsheetApp.getActive();
  var sheet = ss.getSheetByName(folderName);
  if (sheet) {
    Logger.log("found");
  }
  else {
    sheet = ss.insertSheet(folderName);
  }
  sheet.clear();

  sheet.appendRow(["Name", "Date", "Size", "URL", /*"Download",*/ "Description", "Type"]);

  // Loop over files in folder, using file iterator
  while (contents.hasNext()) {
    var file = contents.next();

//    if (file.getMimeType() == MimeType.GOOGLE_SHEETS) { // "SPREADSHEET"
//      // Skip displaying spreadsheets - I don't know why...
//      continue;
//    }

    var data = [ 
      file.getName(),
      file.getDateCreated(),
      file.getSize(),
      file.getUrl(),
      //"https://docs.google.com/uc?export=download&confirm=no_antivirus&id=" + file.getId(),
      file.getDescription(),
      niceFileType( file.getMimeType() )
    ];

    sheet.appendRow(data);

  }
}

/**
 * Get nice, readable file type matching given MimeType. 
 * Refer to https://developers.google.com/apps-script/reference/base/mime-type
 *
 * @param {string} mimeType  File type to match
 *
 * @return {string}          Matched file type, or raw MimeType.
 */
function niceFileType( mimeType ) {
  
  // Supported file types stored in global fileType object for fast lookups.
  if (typeof this.fileType === 'undefined') {
    // Initialize global fileType object first time only.
    this.fileType = {};
    this.fileType[MimeType.BMP] = "BMP";
    this.fileType[MimeType.CSS] = "CSS";
    this.fileType[MimeType.CSV] = "CSV";
    this.fileType[MimeType.FOLDER] = "Folder";
    this.fileType[MimeType.GIF] = "GIF";
    this.fileType[MimeType.GOOGLE_APPS_SCRIPT] = "Google Apps Script";
    this.fileType[MimeType.GOOGLE_DOCS] = "Google Doc";
    this.fileType[MimeType.GOOGLE_DRAWINGS] = "Google Drawing";
    this.fileType[MimeType.GOOGLE_FORMS] = "Google Form";
    this.fileType[MimeType.GOOGLE_SHEETS] = "Google Sheet";
    this.fileType[MimeType.GOOGLE_SLIDES] = "Google Slides";
    this.fileType[MimeType.HTML] = "HTML";
    this.fileType[MimeType.JAVASCRIPT] = "Javascript";
    this.fileType[MimeType.JPEG] = "JPEG";
    this.fileType[MimeType.MICROSOFT_EXCEL] = "XLSX";
    this.fileType[MimeType.MICROSOFT_EXCEL_LEGACY] = "XLS";
    this.fileType[MimeType.MICROSOFT_POWERPOINT] = "PPTX";
    this.fileType[MimeType.MICROSOFT_POWERPOINT_LEGACY] = "PPT";
    this.fileType[MimeType.MICROSOFT_WORD] = "DOCX";
    this.fileType[MimeType.MICROSOFT_WORD_LEGACY] = "DOC";
    this.fileType[MimeType.OPENDOCUMENT_GRAPHICS] = "OpenDoc Graphics";
    this.fileType[MimeType.OPENDOCUMENT_PRESENTATION] = "OpenDoc Presentation";
    this.fileType[MimeType.OPENDOCUMENT_SPREADSHEET] = "OpenDoc Spreadsheet";
    this.fileType[MimeType.OPENDOCUMENT_TEXT] = "OpenDoc Document";
    this.fileType[MimeType.PDF] = "PDF";
    this.fileType[MimeType.PLAIN_TEXT] = "Text";
    this.fileType[MimeType.PNG] = "PNG";
    this.fileType[MimeType.RTF] = "RTF";
    this.fileType[MimeType.SVG] = "SVG";
    this.fileType[MimeType.ZIP] = "Zip Archive";
  }

  // If we know the given filetype, return its nice name.
  return (this.fileType.hasOwnProperty(mimeType)) ? this.fileType[mimeType] : mimeType;
}

Thank you so much for posting! This does exactly what I need it to.

Cheers

Thanks! 👍