Polymer (1.0) - dynamic use xlink:href$ inside template not working properly

Question

i have a custom footer-bar (tabfooter) that creates a set of buttons with inline SVG inside of it (for styling reasons its inline).

I didnt want to put the complete code for all SVG into the attributes, so i just hand over some ids, which are used by the component to determine the paths on its own.

<custom-tabfooter values="{" ids ":["A ","B ","C ","D "]}"></custom-tabfooter>

The component then takes the object with the ID array inside and uses it for repeating the DOM elements that are needed:

<dom-module id="custom-tabfooter">

  <template>

    <template is="dom-repeat" items="{{values.ids}}">
      <button id$="[[addButtonID(item)]]" class$="[[addButtonClass(item)]]">
        <svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="512px" height="512px" viewBox="0 0 512 512" enable-background="new 0 0 512 512" xml:space="preserve">

          <!--<use xlink:href="../assets/img/svg/A-icon.svg#path"></use>-->
          <use xlink:href$="[[replaceSVGPath(item)]]"></use>

        </svg>
      </button>
    </template>

  </template>

  <script>
    Polymer({
      is: "custom-tabfooter",
      properties: {
        values: Array
      },
      ready: function() {
        console.log(this.values.ids);
      },
      addButtonID: function(item) {
        return "btn-footer-icon-" + item;
      },
      addButtonClass: function(item) {
        return "btn-footer-icon btn-" + item;
      },
      replaceSVGPath: function(item) {
        return "../assets/img/svg/" + item + "-icon.svg#path";
      }
    });
  </script>

</dom-module>

This works as intended. But when it comes to the SVG i get confused. There is one line commented out:

<!--<use xlink:href="../assets/img/svg/A-icon.svg#path"></use>-->

This line actually works. Though its only loading a single static SVG by using the internal tag.

When i try to load dynamic SVG content, it fails silently as no errors are thrown nor any SVG has loaded:

<use xlink:href$="[[replaceSVGPath(item)]]"></use>

The output however is pretty similar:

<use xlink:href="../assets/img/svg/A-icon.svg#path"></use>

<use class="style-scope custom-tabfooter" xlink:href="../assets/img/svg/A-icon.svg#path"></use>

The only visible difference is that polymer adds classes to that element.

Anyone an idea?

thanks.Rob

Answer 1

A workaround is to add the attribute statically in addition to the binding

 <use xlink:href="" xlink:href$="[[replaceSVGPath(item)]]"></use>

Polymer has issues creating the attribute, if it already exists it can update it just fine.

Answer 2

This is an issue with Polymer. SVG uses namespaced attributes. To set them properly, you need to call setAttributeNS, but Polymer's attribute bindings aren't namespace-aware, so they can't set these attributes.

This is filed as issue #3060.