addobject.js

var foobar = {};
var name1 = "test-foo-bar";
var name2 = "test-bar-foo";
var addObject = function(parts, object, value) {
	if (parts.length <= 0)
		return value;
	if (!object[parts[0]])
		object[parts[0]] = {};
	object[parts[0]] = addObject(parts.slice(1), object[parts[0]], value);
	return object;
};
addObject(name1.split('-'), foobar, '#cc00ff');
addObject(name2.split('-'), foobar, '#ff00cc');
JSON.stringify(foobar);

output.json

{
    "test": {
        "foo": {
            "bar": "#cc00ff"
        },
        "bar": {
            "foo": "#ff00cc"
        }
    }
}