Q promises pyramid of doom

promises-pyramid.js

var Q = require('q');

function delaydo(x) {
	var deferred = Q.defer();
	setTimeout(function() {
		if (x === 2) {
			console.log("reject: "+x);
			deferred.reject(x);
		}
		else {
			console.log("resolve: "+x);
			deferred.resolve(x);
		}
	}, 1000);
	return deferred.promise;
}

delaydo(1)
.then(function() {
	delaydo(2)
	.then(function() {
		delaydo(3)
		.then(function() {
			delaydo(4);
		})
		.catch(function(errC) {
			console.log("Error handler C: "+errC);
		});
	})
	.catch(function(errB) {
		console.log("Error handler B: "+errB);
	});
})
.catch(function(errA) {
	console.log("Error handler A: "+errA);
});

stdout

resolve: 1
reject: 2
Error handler B: 2