Polymer built-in way to use "sub-pages" and core-submenu?

Question

I'm trying to create a page with core-submenu (and therefore also "subpages" (not a real component)). But as I've seen around the web there's a "problem" with this, since a press on a core-submenu item will trigger the selected event even though naturally one only want it triggered when a child element is pressed on.

I found this link which explain a method to achieve what I want, but this approach relies on ids on all the pages and core-submenu childs. I have no need to "loop"-generate my menu. By not using core-submenu everything is working without even the slightest javascript-code.

Is there some built-in support for core-pages and core-submenu that can be used? In otherwords: A way that does not require any (or minimal) use of javascript?

.
. //some code here
.    
<core-menu theme="core-light-theme" selected="{{selected}}" selectedItem={{item}}>
        <core-submenu icon="settings" label="Favorites">
          <core-item icon="https" label="Hello"></core-item>
          <core-item icon="https" label="World"></core-item>
        </core-submenu>
    </core-menu>
.
. //some code here
.
    <core-animated-pages transitions="cross-fade" selected="{{selected}}">
      <section id="page-1">
        <div cross-fade>Hello content</div>
      </section>
      <section id="page-2">
        <div cross-fade>World content</div>
      </section>
    </core-animated-pages>
.
. //some code here
.

Thank you!

Answer 1

try to use valueattr for ex:

<core-menu theme="core-light-theme">
    <core-submenu icon="settings" label="Favorites"  valueattr="number" selected="{{number}}">
      <core-item icon="https" label="Hello" number="0"></core-item>
      <core-item icon="https" label="World" number="1"></core-item>
    </core-submenu>
      <core-submenu icon="settings" label="Favorites2"  valueattr="number" selected="{{number}}">
      <core-item icon="https" label="Hello2" number="2"></core-item>
      <core-item icon="https" label="World2" number="3"></core-item>
    </core-submenu>
</core-menu>
  <core-animated-pages transitions="cross-fade" selected="{{number}}">
  <section id="page-1">
    <div cross-fade>Hello content - {{number}}</div>
  </section>
  <section id="page-2">
    <div cross-fade>World content - {{number}}</div>
  </section>
      <section id="page-3">
    <div cross-fade>Hello content - {{number}}</div>
  </section>
  <section id="page-4">
    <div cross-fade>World content - {{number}}</div>
  </section>  
</core-animated-pages>

Answer 2

Well, you could dump the idea of having a "shared selected" and instead have something that respond on "core-select" event.

This will work just fine.

    <template is='auto-binding'>
    <core-scaffold>
        <core-header-panel navigation flex>
            <core-toolbar>Menu</core-toolbar>

            <core-menu on-core-select='{{navFunc}}'>

                <core-item label='page1'></core-item>

                <core-submenu label='something' type='submenu'>
                    <core-item label='page2'></core-item>
                    <core-item label='page3'></core-item>

                    <core-submenu label='super submenu' type='submenu'>
                        <core-item label='page4'></core-item>
                        <core-item label='page5'></core-item>
                    </core-submenu>

                </core-submenu>

                <core-submenu label='more here' type='submenu'>
                    <core-item label='page6'></core-item>
                    <core-item label='page7'></core-item>
                </core-submenu>

            </core-menu>

        </core-header-panel>

        <core-animated-pages selected='{{myselection}}' valueattr='label'>
            <section label='page1'>Page1</section>
            <section label='page2'>Page2</section>
            <section label='page3'>Page3</section>
            <section label='page4'>Page4</section>
            <section label='page5'>Page5</section>
            <section label='page6'>Page6</section>
            <section label='page7'>Page7</section>
        </core-animated-pages>

    </core-scaffold>
    </template>
    <script>
        var template = document.querySelector('template[is="auto-binding"]');

        template.navFunc = function(e, detail){
            if (detail.item.getAttribute('type') !== 'submenu' && detail.isSelected == true) {
                template.myselection = detail.item.getAttribute('label');
            }
        }
    </script>