Extending an element and adding an attribute

Test to extend and element and add additional attributes. The second component takes an additional attribute, but doesn't declare the parent attribute in `attributes=`

by jamstooks

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/polymer/0.1.4/platform.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/polymer/0.1.4/polymer.js"></script>
<polymer-element
    name="test-parent-component"
    attributes="firstparam">
    <template>
        <div>
            All params: {{allParams}}
        </div>
    </template>
</polymer-element>

<polymer-element
    name="test-child-component"
    attributes="secondparam"
    extends="test-parent-component">
</polymer-element>

<h1>Parent:</h1>
<test-parent-component firstparam="p"></test-parent-component>
<h1>Child:</h1>
<test-child-component firstparam="p" secondparam='c'></test-child-component>

JavaScript

/*
    The second component takes an additional attribute,
    but doesn't declare the parent attribute in `attributes=`
*/

Polymer('test-parent-component', {
    
    ready: function() {
        this.allParams = ""
    },
    
    firstparamChanged: function() {
        this.getParams();
    },
    
    getParams: function() {
        this.allParams = this.firstparam;
    }
});

Polymer('test-child-component', {
    
    secondparamChanged: function() {
        this.getParams();
    },
    
    getParams: function() {
        this.super();
        this.allParams += this.secondparam;
    }
});