--- title: add() --- ```js Attributes attributes.add(string key, string value) ``` Adds `value` to the attribute identified by `key`. Adding multiple values to the same key will result in them being joined together (with a space) when rendering. ```js let { Path, paths } = part.shorthand(); // This will render as: class="classA classB" paths.demo = new Path(); paths.demo.attributes.add('class', 'classA'); paths.demo.attributes.add('class', 'classB'); // This does the same thing: paths.demo = new Path() .attr('class', 'classA') .attr('class', 'classB'); // This also has the same result: paths.demo = new Path() .attr('class', 'classA classB'); ```