Custom Elements are stripped from dashboard widgets

[tajakobsen]

Problem

We use Custom Elements (Web components) – which is part of the web platform – as the glue between JavaScript and HTML in our applications.

It appears that Custom Elements are stripped away from the rendered markup in dashboard widgets (and perhaps other widgets too).

Example

This controller...

exports.get = function() {
  var markup = '<div><my-element>Testing</my-element></div>'

    return {
        body: '<widget>' + markup + '</widget>',
        contentType: 'text/html'
    };
};

...will render:

<widget class="widget-contents">
  <h5 class="widget-header">My dashboard widget</h5>
  <div>Testing</div>
</widget>

As we can see the <my-element> custom element has been removed.

Expected behaviour

Custom Elements should be present in the markup just like other elements.

[alansemenov]

@tajakobsen custom elements are potentially unsafe and get stripped with sanitisation of widget's html code. we will discuss a possibility of supporting a config setting which will allow custom elements in widgets.