Handlebars array access with dynamic index - handlebars.js

Question

How can I access to an array element inside handlebars template using a variable instead of an hardcoded value?
I need to do something like:
{{#each condition in conditions}}
{{App.ops.[condition.op].name}}
{{/each}}
at the moment doesn't give me a parse error but on runtime doesn't return me nothing.
If i do something like this:
{{App.ops.[1].name}}
it works but it's not what i'm looking for

Answer 1

Related to my answer on another question
You can use the built-in lookup helper:
The lookup helper allows for dynamic parameter resolution using Handlebars variables. This is useful for resolving values for array indexes.
Using lookup, your example could be written as
{{#each condition in conditions}}
{{#with (lookup ../App.ops condition.op)}}
{{name}}
{{/with}}
{{/each}}
(Note that without knowledge of the structure of your data, I'm making an assumption about the location of App.ops.)

Answer 2

You can write a simple helper just to get value from array
Handlebars.registerHelper('getmyvalue', function(outer, inner) {
return outer[inner.label];
});
and then use it in template like
{{#each outer}}
{{#each ../inner}}
{{getmyvalue ../this this }}
{{/each}}
../this references to current outer item, and this - to current inner item
Example of data coming to template:
{
outer: {
1: { foo: "foo value" },
2: { bar: "bar value" }
},
inner: {
1: { label: "foo" },
2: { label: "bar" }
}
}

Answer 3

You need to create a helper for your problem. Below is the sample solution to your problem using index values. If you want to use some conditions you can also do that.
Handlebars.registerHelper("each_with_index", function(array, options) {
if(array != undefined && array != null && array.length > 0){
var html = new StringBuffer();
for (var i = 0, j = array.length; i < j; i++) {
var item = array[i];
item.index = i+1;
// show the inside of the block
html.append(options.fn(item));
}
// return the finished buffer
return html.toString();
}
return "";
});
Then you can do something like this
{{#each_with_index condition in conditions}}
{{App.ops.[condition.index].name}}
{{/each_with_index}}