Autogrow angular directive for textareas

autogrow.js

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

    // styles that influence on text
    var props = [
        'webkitBoxSizing', '-webkit-box-sizing', 'padding', 'font', 'width', 'textIndent',
        'whiteSpace', 'wordSpacing', 'wordWrap', 'textAlign'
    ];

    return {
        restrict: 'A',
        require: 'ngModel',
        replace: false,
        link: function ($scope, $element, attrs, ngModel) {
            var $copy = $('<div></div>'),
                minHeight = $element[0].clientHeight,
                computedStyles = window.getComputedStyle($element[0]),
                stylesheets = $copy[0].style,
                val;

            // copy styles of original element
            props.forEach(function (prop) {
                if (computedStyles.hasOwnProperty(prop)) {
                    stylesheets[prop] = computedStyles[prop];
                }
            });

            // make out copy element invisible
            $copy.css({
                height: 'auto',
                position: 'absolute',
                top: '-9999px',
                left: '-9999px'
            });

            $(document.body).append($copy);

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

                    return r;
                }

                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) + ' ' });
                $copy.html(val);

                $element.css('height', Math.max($copy[0].offsetHeight, minHeight) + 'px');
            }

            // update on value changed
            // note: use throttle when you expect that value will change very frequently
            $scope.$watch(function () {
                return ngModel.$modelValue;
            }, update);


            $scope.$on('$destroy', function () {
                // remove copy element on scope destroy
                $copy.remove();
            });
        }
    }

});

http://jsfiddle.net/jEmhu/