Auto Expanding/Grow textarea directive for AngularJS

gistfile1.js

/*
  Updated event handler to handle paste with mouse right button properly.
  Also changed that it works properly with Angular Material Textarea field
*/

/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2013 Thom Seddon
 * Copyright (c) 2010 Google
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.

 * Adapted from: http://code.google.com/p/gaequery/source/browse/trunk/src/static/scripts/jquery.autogrow-textarea.js
 *
 * Works nicely with the following styles:
 * textarea {
 *  resize: none;
 *  word-wrap: break-word;
 *  transition: 0.05s;
 *  -moz-transition: 0.05s;
 *  -webkit-transition: 0.05s;
 *  -o-transition: 0.05s;
 * }
 *
 * Usage: <textarea auto-grow></textarea>
 */

define([ 'app' ], function(app) {
	'use strict';

	app.directive('autogrow', [ function() {

		return function(scope, element, attr) {
			var minHeight = element[0].offsetHeight;
			var $shadow = angular.element('<div></div>').css({
				position : 'absolute',
				top : -1000,
				left : -1000,
				//zIndex: 999999999,
				wordWrap: 'break-word',
				fontSize : element.css('fontSize'),
				fontFamily : element.css('fontFamily'),
				resize : 'none'
			});
			angular.element(document.body).append($shadow);

			var update = function() {
				var times = function(string, number) {
					for ( var i = 0, r = ''; i < number; i++) {
						r += string;
					}
					return r;
				};

				var val = element.val().replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/&/g, '&amp;').replace(/\n$/, '<br/>&nbsp;').replace(/\n/g, '<br/>').replace(/\s{2,}/g, function(space) {
					return times('&nbsp;', space.length - 1) + ' ';
				});
				$shadow.html(val);
				
				$shadow.css('width', Math.max(element[0].offsetWidth - parseInt(element.css('paddingLeft') || 0) - parseInt(element.css('paddingRight') || 0)- parseInt(element.css('borderWidth') || 0)) + 'px').css('lineHeight', element.css('lineHeight'));
				element.css('min-height', Math.max($shadow[0].offsetHeight, minHeight) + 'px');
			};

			element.bind('keyup paste', function(){setTimeout(update, 0);});
			update();
			
			//destroy div helper
			scope.$on('$destroy', function() {
			 $shadow.remove();
			});
	};

	} ]);

});