urn instance && instance.__key__;
},
indexForElement: function(el) {
var instance = this.modelForElement(el);
return instance && instance[this.indexAs];
}
});

Polymer({
is: "array-selector",
properties: {
items: {
type: Array,
observer: "_itemsChanged"
},
selected: {
type: Object,
notify: true
},
toggle: Boolean,
multi: Boolean
},
_itemsChanged: function() {
if (Array.isArray(this.selected)) {
for (var i = 0; i < this.selected.length; i++) {
this.unlinkPaths("selected." + i);
}
} else {
this.unlinkPaths("s