[0.9] if="{{ 1 < 2 }}" not supporded?!

[teckays]

This si not working!

<template is="dom-repeat" items="{{items}}">
    <template is="dom-if" if="{{index == 2}}">
      <!-- show third item -->
    </template>
</template>

a bug or a feature?

[teckays]

http://jsbin.com/qevuzupoti/1/edit

[arthurevans]

Feature. No expressions are supported in bindings, except for ! and inline functions.

https://www.polymer-project.org/0.8/docs/migration.html#data-binding

In general, expressions like this can be replaced with inline functions or computed properties, like this:

<template is="dom-if" if="isIncluded(index)">

However, it appears that inline functions can't be defined on an auto-binding template. Not sure whether that's a bug or not.

[arthurevans]

Opened #1500 for autobinding template issue. Closing this because it's working as intended.

[chuckh]

@arthurevans I think you mean this:

 <template is="dom-if" if="{{isIncluded(index)}}">

I have a working example at http://plnkr.co/edit/7KKqwIVVKVXt44nkuBgi?p=preview using this syntax with a custom element. It does not work using auto-bind

[arthurevans]

Yep, I was writing too fast there. Thanks, Chuck.

[teckays]

Ok, thanks for pointing out!

[kevinpschaaf]

@teckays Also note, the case you showed is a good candidate for using the filter feature of dom-repeat. It doesn't support filtering based on index (so if that's really your use case maybe not), but if your item has the criteria you would use to switch the dom-if, you'd be better using filter than dom-if, since you'd be stamping less stuff.

http://jsbin.com/dogizasicu/1/edit?html,console,output

[teckays]

@kevinpschaaf didn't know about the filter attribute, thank you for sharing, will definitely use it when appropriate. The use case I have requires stamping all items but some of them treat in a different way.