Child polymer element with array type attribute value

[sume...@gmail.com]

I am calling a polymer element within another element. The inner polymer element has a published attribute to which I am binding JSON from the parent polymer. However it is not getting reflected.

<polymer-element name="parent-test" attributes="testData">
    <template>

        This is Parent test
        <child-test testdatachild="{{testData}}"></child-test>

    </template>
    <script>
        Polymer('parent-test', {
            testData: [],
            ready: function () {
                debugger;
                this.testData = [1, 2, 3, 4]
            }
        });
    </script>
</polymer-element>


<polymer-element name="child-test" attributes="testDataChild">
    <template>
        <!--{{testDataChild}}-->
        <template repeat="{{test in testDataChild}}">
            {{test}}
        </template>


    </template>
    <script>
        Polymer('child-test', {
            testDataChild: [],
            ready: function () {
                debugger;
            }
        });
    </script>
</polymer-element>

I am not sure what could be the problem here.

Seems like I am not having the actual parentContent at the time of generating the child-polymer-element. If I assign hardcoded values in ready function for this.parentContent, it doesnt work as well. If I assign hardcoded values in create function for this parent.Content, it works. So, I am not not sure if this is something related to generating the child polymer element before the values getting binded to parent.

Also, it works if testDataChild is a string and not an array

[Daniel Llewellyn]

 

 

From: polym...@googlegroups.com [mailto:polym...@googlegroups.com] On Behalf Of sume...@gmail.com

Seems like I am not having the actual parentContent at the time of generating the child-polymer-element. If I assign hardcoded values in ready function for this.parentContent, it doesnt work as well. If I assign hardcoded values in create function for this parent.Content, it works. So, I am not not sure if this is something related to generating the child polymer element before the values getting binded to parent.

Also, it works if testDataChild is a string and not an array

Hi, I believe you’re hitting the condition where arrays, because they are objects, are shared between every instance of your element in singleton fashion. To work around this you need to not define the array, which will be populated by the attribute binding, in the prototype but instead create them in a “created” call-back inside your element’s script.

The reason you’re seeing it work correctly with strings is because, unlike arrays and objects as I said above, strings and numbers are not shared between instances of your element but are unique to each instance.

Regards,

Daniel Llewellyn

[Arthur Evans]

Actually, I think the problem is the reverse. You should see a log message that says: 

Attributes on child-test were data bound prior to Polymer upgrading the element. This may result in incorrect binding types.

If you flip the order of definitions, child-test is defined before you try to define parent-test, and the data binding gets initialized correctly.

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