Combine jQuery Globalize with underscore.js template?

Question

I'm using an underscore template to create an HTML list, this list contains a date field that I would like to globalize. A simplification of the template looks like this:

<li>Date: <%= date %> </li>

This date is a Javascript date object, so don't want to print the value directly, I would like to print it using globalize. Without the template the solution should look like this:

var html = "<li>Date: " + Globalize.format(settings.get('lastUpdate'),'F') + "</li>";

Do you think I can use the template to achieve this or I must use a workaround?

Answer 1

You can call any globally accessible function inside your template. So, if Globalize is global (i.e. a property of window), then this template:

<script id="tmpl" type="text/html">
    <li>Date: <%= Globalize.format(date, 'F') %></li>
</script>

will work with this JavaScript:

_.template($('#tmpl').html(), {
    date: some_date_that_globalize_understands
});

If you don't have Globalize globally available then you could:

window.Globalize = Globalize;

to make it globally available or just add it to the template's namespace manually:

_.template($('#tmpl').html(), {
    Globalize: Globalize,
    date:      some_date_that_globalize_understands
});

Demos:

1. Global Globalize through window.Globalize..
2. Local Globalize through the _.template parameters..

There's really nothing special about the Underscore templates, the stuff inside <%= %> is just JavaScript code that ends up wrapped in a with block. You can even see the function's source by looking at the source property on the returned template function:

var t = _.template($('#t').html());
console.log(t.source);

and you'll see some fairly simple (if ugly) JavaScript like this:

function(obj){
var __p='';var print=function(){__p+=Array.prototype.join.call(arguments, '')};
with(obj||{}){
__p+='\n    '+
( Globalize.mangle(pancakes) )+
'\n';
}
return __p;
}

That + (Globalize.mangle(pancakes) )+ bit is what <%= Globalize.mangle(pancakes) %> gets turned into. No magic, no special parsing of the contents of <%= ... %>, just a simpleminded (but effective) conversion to JavaScript.