Autogrow directive for textarea

autogrow.js

$module.directive('autogrow', autogrowDirective);

/**
 * @directive autogrow
 */
function autogrowDirective() {
	return {
		link: linker,
		require: '?ngModel'
	};

	function linker($scope, $element, $attrs, ngModel) {
		var min = $attrs.rows | 0 || 1;
		var max = $attrs.maxRows | 0;

		function getSize() {
			return String(ngModel && ngModel.$viewValue || $element.val()).split('\n').length;
		}

		$element.on('keyup focus', function() {
			var size = getSize();

			if (size >= min && (!max || (max && size <= max))) {
				$element.attr('rows', size);
			}

		});

		$scope.$on('$destroy', function() {
			$element.off('keyup focus');
		});
	}
}