Google Document Script for insert at cursor: current date and last updated date

code.gs

/* opened. Use it to add custom menus to Google Docs that allow the user to run
 * custom scripts. For more information, please consult the following two
 * resources.
 *
 * Extending Google Docs developer guide:
 *     https://developers.google.com/apps-script/guides/docs
 *
 * Document service reference documentation:
 *     https://developers.google.com/apps-script/reference/document/
 */
function onOpen() {
  // Add a menu with some items, some separators, and a sub-menu.
  DocumentApp.getUi().createMenu('Utilities')
      .addItem('Insert Current Date', 'insertCurrentDate')
      .addItem('Insert Last Updated Date', 'insertLastUpdatedDate')
      .addToUi();
}

/**
 * Inserts the date at the current cursor location in boldface.
 */
function insertCurrentDate() {
  var cursor = DocumentApp.getActiveDocument().getCursor();

  if (cursor) {
    // Attempt to insert text at the cursor position. If insertion returns null,
    // then the cursor's containing element doesn't allow text insertions.
    var date = Utilities.formatDate(new Date(), "GMT", "yyyy-MM-dd"); // "yyyy-MM-dd'T'HH:mm:ss'Z'"
    var element = cursor.insertText(date);
    if (element) {
      element.setBold(true);
    } else {
      DocumentApp.getUi().alert('Cannot insert text at this cursor location.');
    }
  } else {
    DocumentApp.getUi().alert('Cannot find a cursor in the document.');
  }
}


function insertLastUpdatedDate() {
   
  var id = DocumentApp.getActiveDocument().getId();
  var lastUpdated = DriveApp.getFileById(id).getLastUpdated();
  var date = Utilities.formatDate(lastUpdated, "GMT", "yyyy-MM-dd"); // "yyyy-MM-dd'T'HH:mm:ss'Z'"  
  
  var cursor = DocumentApp.getActiveDocument().getCursor();
  
  if (cursor) {
    var element = cursor.insertText(date);
    if (element) {
      element.setBold(true);
    } else {
      DocumentApp.getUi().alert('Cannot insert text at this cursor location.');
    }
  } else {
    DocumentApp.getUi().alert('Cannot find a cursor in the document.');
  }
};

Thanks for sharing! 🎉
For some reason, the onEdit(e) doesn't work for Google Docs (and according to the documentation it only gets triggered when a Spreadsheet cell changes, so, no support for Google Docs, yet!), I wanted to run a replace-placeholder-with-content logic on edit, and adding a menu to manually do that was a good plan B. Thanks again. 😁