Passing spacebar data context from parent template to child - meteor

Question

I am having a silly trouble with nested templates. I want to create a dropdown menu with 4 main categories and about 2-3 subcategories for each main category.
<template name="Warehouselist">
<li class="dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#"> {{warehouse}} <span class="caret"></span></a>
<ul class="dropdown-menu">
{{#each Forms}}
{{>Form}} //Pass {{warehouse}} here
{{/each}}
</ul>
</li>
</template>
<template name="Form">
<li id="EWPacking">{{FormName}}</li>
</template>
The problem is that I don't know how to pass the {{warehouse}} data to the child template's helper in order so I can do something like this.
Template.bonus.helpers({
Userform: function(){
return UserForms.find({});
},
warehouse: function(){
return Warehouse.find({});
},
});
Template.Warehouselist.helpers({
Forms: function(Warehouse){
return Forms.find({Warehousename:Warehouse});
}
});
The point is that the helper of the child template has to return different data, depending on what is the Category of the parent element.

Answer 1

Use parent data context in the child template 'Form':
<template name="Warehouselist">
<li class="dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#">{{warehouse}}<span class="caret"></span>
</a>
<ul class="dropdown-menu">
{{#each Forms}}
{{>Form}}
{{/each}}
</ul>
</li>
</template>
<template name="Form">
<li id="EWPacking">
{{FormName}} - {{../warehouse}}</li>
</template>
And change your javascript for the Warehouselist template helper. Get the warehouse from the data context with Template.currentData() and pass it in the Forms.find().
Like this:
Template.Warehouselist.helpers({
Forms: function(){
var warehouse = Template.currentData().warehouse;
console.log('warehouse:', warehouse);
return Forms.find({Warehousename: warehouse});
}
});
If you want to pass warehouse to the child template like you asked use:
(BUT: this is not needed if you follow the solution above!)
{{#each Forms}}
{{>Form warehouse=warehouse}}
{{/each}}