require({
  baseUrl: '/src'
}, [ 'html-janitor' ], function (HTMLJanitor) {
  var janitor = new HTMLJanitor({
    tags: {
      p: []
    }
  });

  var p = document.createElement('p');
  p.setAttribute('style', 'font-size: 16px;');
  p.setAttribute('class', 'example-class');
  console.log(janitor.clean(p.outerHTML));
});

require({
  baseUrl: './src'
}, [ 'html-janitor' ], function (HTMLJanitor) {
  var janitor = new HTMLJanitor({
    tags: {
      p: []
    }
  });

  var p = document.createElement('p');
  p.setAttribute('style', 'font-size: 16px;');
  p.setAttribute('class', 'example-class');
  console.log(janitor.clean(p.outerHTML));
});

Use relative path for baseURL