How can I add an additional binding to an element inside a dom-repeat?
<p>I have a template dom-repeat element.  I know that I can define the <code>items</code> attribute from an array, so that <code>item</code> can be accessed inside the template.  However, I don't know how to access other objects inside the template if I bind them to customer polymer elements.</p>
<p>In this example, <code>items</code> is being defined by <code>someItems</code>, and <code>item</code> is passed into the element <code>&lt;my-el&gt;</code>.  I also have a string <code>mine</code> that I want to pass into <code>&lt;my-el&gt;</code> and use there.  I currently have the idea to do this in app-el.html, which contains the dom-repeat template:</p>
<h3>app-el.html</h3>
<pre><code>&lt;template is=&quot;dom-repeat&quot; items=&quot;[[someItems]]&quot;&gt;
  &lt;my-el item=[[item]] mine=&quot;[[mine]]&quot;&gt;&lt;/my-el&gt;&lt;br&gt;
&lt;/template&gt;
</code></pre>
<p>In theory, I would be able to access both in my-el.html like this:</p>
<h3>my-el.html</h3>
<pre><code>[[item]] [[mine]]
</code></pre>
<p>However, when I try to access <code>mine</code> from inside <code>&lt;my-el&gt;</code> it is undefined.  How can I correctly pass in this string so I can access it?</p>
<p>An MCVE can be found on this <a href="https://plnkr.co/edit/8LPlwWBBCVfRcVfIklz1?p=preview" rel="nofollow noreferrer">Plunker</a>.  Note how the <code>item</code> string is defined inside <code>&lt;my-el&gt;</code> but the <code>mine</code> string is not.</p>