Add root context to data when using in-built #each and #which helpers

[williamcoates]

Sometimes you need to access variables from the root context in any other sub-context. It can be very painful having to always figure out the right path back to the root context when in multiple loops.

For example in my app i have an i18n object bound to the root context, that my i18n helper needs to access. If I can't easily access the root context i need to workaround this by backing up the context like so

{{#with ../..}} {{i18n 'Foo'}{{/with}}

This is painful, and not always possible if the above code is in a partial which might be used from different contexts.

This patch simply adds the root context to the data hash in the #each and #which helpers, so you can build helpers which access the root context like so:

function(string, options) {
       return options.data.root.i18n.__(string);
}

It would be even cooler if you could do this in your templates:

{{@data.root.foo}}

But this would require altering the parser AFAIK which would require a bit more work...

Not sure on the etiquette for updating the distro, so I left those unchanged in this commit.

[spikebrehm]

Does this mean in templates you could use {{@root}}?

[williamcoates]

No, its just adds root to the context so your helpers can use it

[BrewDawg]

You guys are off your game, it's easy ...

I have created one see http://www.my2ndgeneration.com/TemplateLanguageDoc.aspx#xroot

Basically, add this helper and bingo {{xRoot}} will take you to the top ...

I always pass my JSON data into handlebars like this:

{ data: self.data } 

thus the code below always returns "data" when it sees the xRoot tag and takes me to the top

Handlebars.JavaScriptCompiler.prototype.nameLookup = function (parent, name, type) {

    if (name.indexOf("xRoot") === 0) {
        return "data";
    }

    if (/^[0-9]+$/.test(name)) {
        return parent + "[" + name + "]";
    } else if (Handlebars.JavaScriptCompiler.isValidJavaScriptVariableName(name)) {
        return parent + "." + name;
    }
    else {
        return parent + "['" + name + "']";
    }
};

By the way, I've built a tool that allows you to execute full Handlebar templates on the desktop, without a browser, it's pretty cool

See http://www.tiraggo.com/movies/M2G_Desktop_Reveal.html

[jonschlinkert]

👍 would be nice to see this merged

[kpdecker]

Thanks for the PR and sorry it took me so long to look at this. We're going to do something like this but I want it to be generically accessible rather than just within these helpers. I've attached a PR to #392 to this end.

[BrewDawg]

So how would use use this? I guess it's @root ? I would have thought you would have been {{root}} or {{root.Items}}

Can you show us how you would use root to get back up to the root of the data and access some properties?