Google Docs Script for Inserting Formatted Date with Month Name via a Macro

gdocs-formatted-date-macro.js

/**
 * Helper functions to make formatting the date easier
 */
Date.prototype.getMonthNameShort = function() {
		    return Date.month_names_short[ this.getMonth() ];
};

Date.month_names_short = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

Date.prototype.getDateEnding = function() {
    var currentDate = this.getDate();
    if ( [1,21,31].indexOf( currentDate ) > -1 ) {
        return Date.date_endings[0];
    } else if ( [2,22].indexOf( currentDate ) > -1 ) {
        return Date.date_endings[1];
    } else if ( [3,23].indexOf( currentDate ) > -1 ) {
        return Date.date_endings[2];
    } else {
        return Date.date_endings[3];
    }
};

Date.date_endings = [ 'st','nd','rd','th' ];

/**
 * The onOpen function runs automatically when the Google Docs document is
 * 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 Date', 'insertAtCursor')
      .addToUi();
}

/**
 * Inserts the sentence current formatted date at the current cursor location in boldface.
 */
function insertAtCursor() {
  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 ndate = new Date();
    var fdate = ndate.getMonthNameShort() + ndate.getDate() + ndate.getDateEnding() + '-' + ndate.getFullYear();
    
    var element = cursor.insertText(fdate);
    if ( !element ) {
      DocumentApp.getUi().alert('Cannot insert text at this cursor location.');
    }
  } else {
    DocumentApp.getUi().alert('Cannot find a cursor in the document.');
  }
}