Polymer global variables document may be wrong~

Question

I'm new to polymer and now reading the document. But I'm confused about the following document:

(function() {
var values = {};

Polymer('app-globals', {
   ready: function() {
     for (var i = 0; i < this.attributes.length; ++i) {
       var attr = this.attributes[i];
       values[attr.nodeName] = attr.nodeValue;
     }
   }
});
})();

and then define the global variables like this:

<app-globals firstName="Addy" lastName="Osmani"></app-globals>

I've tried this way but I can't get any variables via app-globals, the Value is absolutely a local variable for it is not with a this. started, then how can I get the value via app-globals?

Answer 1

This looks like a mistake in the documentation. I believe the intent is something like this:

<polymer-element name="app-globals" attributes="values">
  <script>
  (function() {
    var values = {};

    Polymer('app-globals', {
       ready: function() {
         // this bit at least is missing from the example
         this.values = values;
         // initialize values from attributes (note: strings only)
         for (var i = 0; i < this.attributes.length; ++i) {
           var attr = this.attributes[i];
           values[attr.nodeName] = attr.nodeValue;
         }
       }
    });
  })();
  </script>
</polymer-element>

This way the data is available from any instance of app-globals as instance.values. I also published values so that you can bind to it.

... in some element template ...

<app-globals values="{{globals}}"></app-globals>
<h2>{{globals.header}}</h2>