gistfile1.js

// Extend NodeList with a rotateClass method that will rotate among a list of
// classArr, and optionally remove them as part of the rotation.
dojo.extend(dojo.NodeList, {
  rotateClass: function(classArr, remove) {
	var l = classArr.length;
	return this.forEach(function(n) {
		var rotated = false;
		for(var i=0; i<l; ++i) {
			if(remove && i == (l-1)) {
				// Found last class, and remove == true, rotate to none
				dojo.removeClass(n, classArr);
				rotated = true;
				break;
			} else if(dojo.hasClass(n, classArr[i])) {
				// Found one of the classes, rotate to next one in array
				dojo.removeClass(n, classArr[i]);
				dojo.addClass(n, classArr[(i+1) % l]);
				rotated = true;
				break;
			}
		}
		
		// If we didn't find any rotatable class, and the remove == true
		// add the first class.  This allows rotating from a -> b -> none -> a,
		// but also means that a node that initially starts with none will
		// be rotated to a.
		if(!rotated && remove) {
			dojo.addClass(n, classArr[0]);
		}
	});
  }
});