In polymer-dart how do I count inside a repeating template - templates

Question

Say I've got a repeating template:
<template bind repeat id='my-template'>
This is the bound value: <span id="#myid[x]"> {{}} </span>
</template>
what can I replace [x] with that will be unique? Access to the loop counter would do the trick, but I'm open to suggestions.

Answer 1

I'm adding some utilities to Fancy Syntax (Polymer.dart's default binding syntax now) to help with this, but the basic outline is to run your collection though a filter that will add indices and return a new Iterable.
Here's some code that will do it now though:
import 'package:fancy_syntax/fancy_syntax.dart';
import 'package:mdv/mdv.dart';
Iterable<IndexedValue> enumerate(Iterable iterable) {
int i = 0;
return iterable.map((e) => new IndexedValue(i++, e));
}
class IndexedValue<V> {
final int index;
final V value;
IndexedValue(this.index, this.value);
}
main() {
query('#my-template')
..bindingDelegate = new FancySyntax(globals: {
'enumerate': enumerate,
})
..model = ['A', 'B', 'C'];
}
<template bind id='my-template'>
<template repeat="{{ item in this | enumerate }}">
This is the bound value: <span id="#myid-{{ item.index }}">{{ item.value }}</span>
</template>
</template>
I'm trying to get a bunch of utilities like Python's itertools into a library for uses like this. I'll update when they're available.