Should marionette backbone model fields be automatically available for templates - templates

Question

I have a collection calling a remote REST server and getting back a JSON object containing fields including arrays. My Model is being called on each iteration through the collection, and I can get one of the fields to render in my template. Here's where things get strange...
If I do the following in the template:
<%= name %>
I can get the name field to output. However, any other fields will not render, unless I create some defaults at the beginning of the Model thus:
defaults: {
name: '',
phone: '',
age: ''
}
So, if I include this, I can render those fields. Should I have to do that on a model to use it's fields?
... as requested by n8eil
Template:
<script type="text/template" id="pos-list-item">
<%= name %>, <%= description %>, <%= cost %>
</script>
JSON Object:
{
"itemCount": 3,
"items": [
{
"uri": "/item/1234",
"name": "Soda Drink",
"description": "A fizzy drink",
"price": [
{
"costType": "A",
"cost": 3.5
}
],
"live": true,
"created": "2013-10-07 18:22:29"
},
{
"uri": "/item/12345",
"name": "Choco bar",
"description": "A nice snack",
"price": [
{
"costType": "B"
"cost": 1.75
}
],
"live": true,
"created": "2013-10-07 18:22:29"
}
]
}
Changed some data for project privacy but this is essentially the layout of the JSON object. I need 'name', 'description' and 'cost' to appear in the template as above. I can log 'price' out to the console and it shows as an object but I cannot single out the 'cost' field...

Answer 1

http://jsbin.com/eHoPAri/1/edit?html,js,console,output
I went ahead and mocked up some Marionette structures for this data, not sure if they're close to what you're doing. The only thing I needed to change for the template was that 'cost' is inside an object inside the 'price' array, so you need to reference it by 'price[0].cost'. Otherwise no, you should not need default properties on a model in order for them to be rendered in the template, but you will get an error if you try to reference a property not found on the model.
You could also put in a method to add a 'cost' property to the model when it's loaded so you don't have to reference it from the array :
var itemModel = Backbone.Model.extend({
parse : function(response, options){
return _.extend(response, { 'cost' : response['price'][0]['cost'] })
}
});
Hope this helps

Answer 2

Yes, the field would have to exist when rendering that template. However, you could modify the template and not have to include defaults:
<%= name ? name : '' %>