jQuery Isotope — sort by category, but specify which comes first

Question

I'm looking for a type of sort behaviour, one that would match a specific category and bring this to the front of the listing. Like a filter would, except without removing other items.

Imagine these category items in an Isotope grid:

• Red
• Green
• Blue
• Red
• Green
• Blue

If I sort by category, it does so alphabetically to show:

• Blue
• Blue
• Green
• Green
• Red
• Red

What I'd like is to float a specific category to the front, e.g. "Green", like so:

• Green
• Green
• Red
• Red
• Blue
• Blue

Is this possible?

I've tried adding a getSortData function for each category like so:

      green : function( $elem ) {
        var $greenItems = $elem.filter('.green');            
        var $otherItems = $elem.filter(':not(.green)');
        return $greenItems.add($otherItems);
      }
      // repeat for blue, red, etc

But that didn't work.

Answer 1

This worked for me:

green : function( $elem ) {
    var isGreen = $elem.hasClass('green');
    return (!isGreen?' ':'');
},
// etc

Demo: http://jsfiddle.net/Yvk9q/9/