For nested helpers: get the @ variables of the outer helper from the inner one

[kpdecker]

Following this conversation, I think it would be very handy to be able, in nested helpers, to get the @ variables of the outer helper from the inner one.

{{#each outer}}
    {{#each inner}}
        <!-- How to get the outer index here? -->
    {{/each}}
{{/each}}

I am not sure what should be the syntax though...

../@index
@../index

Thanks

[HoffmannP]

Just a hint for me and others that like to implement that: We'd need to add the syntax to the lexer as @Index is a DATA node (there is no seperate @), / is a SEP and there is neither a construct for SEP-DATA nor is ../ included in the DATA definition (ID-DATA is also not defined).

[HoffmannP]

Also I would prefer ../@Index, any comment on how this should be implemented?

[HoffmannP]

So, I dived a little deeper and think that prior to any coding there should be an understanding which way this should work:

• We should state more precisely if
  1. every data/@ variable should be accessible or
  2. only index or
  3. index and key
• What should the accessor variable look like:
  1. ../@index
  2. @../index
  3. @@index or
  4. any other already possible tokken alike @oldindex (just using any another keyword)
• How should that be implemented, I propose two ways
  1. Object.getPrototypeOf(data).index (or any more complicated wrapper for IE<9 compatibility)
  2. Augmenting data with an old-key containing the previous block
  3. Saving all variables of the outer block by renaming them (e.g. index -> oldindex)

Personally, I propose 1-1-1, but would try to realize any other solution a majority votes for it (@wycats should probably delimit the possibilities to that he would accept as merges).

[master-lincoln]

I really need this feature currently. I found a suggestion for a hacky workaround on Stackoverflow:

Handlebars.registerHelper('setIndex', function(value){
    this.index = Number(value);
});

used this way:

{{#each company}}
{{setIndex @index}}
{{#each employee}}
  {{../index}}
{{/each}}
{{/each}}

Sadly this doesn't seem to work if the inner loop is rendered from a template:

{{#each company}}
{{setIndex @index}}
{{#each employee}}
  {{>my-template}}
{{/each}}
{{/each}}

where my-template also contains {{../index}}.
Error is Cannot read property 'index' of undefined.
Do you know a temporary solution for that until a proper implementation is ready?

[HoffmannP]

Haven't tried it, but I'd recommend to create a new dataframe and not set this.index but data.outerindex to the outer index.
This is away I could imagine it could work - but I didn't try it and don't know how and if the data-option is transfered to partials.
Please also comment on my questions.

[uoziod]

Hey guys!
Something is going on here?

[jrmlstf]

I needed this feature too, so i used the hacky helper to achieve this. Would be really great to add this feature.

[wycats]

The original design of this feature was that @properties should inherit down the scope chain. Is that not working?

[kpdecker]

@wycats nested each helpers will override one index value

[HoffmannP]

I'm still not shure if there is a stable method to access overridden properties. Neither

Object.getPrototypeOf(data) // nor
data.__proto__

seem to be supported by all major browsers so the only stable way seems to create an 'old' property that links to the old data-frame, not shure if that works for templates though.
The next question is how to address that old frame. I proposed different possibilities in my previouse post.

[kpdecker]

Released in v2.0.0-alpha.1

[davis]

so how do we use this?

[kpdecker]

@davis the tests provide examples, but this could use formal documentation as well.

@../foo and similar should work.

[davis]

got it. Thanks!