sample.js

foo(function(err, fres) {
	var arr = [];
	fres.forEach(function(item) {
		bar(item, function(state) {
			arr.push({ item: item, state: state });
		});
	});
	res.render(page, { arr: arr }); 
	// obviously arr is empty.
	// how would I use promises to handle this?
});