thenable bluebird native

var Promise = require('bluebird');
function a(val){
	 return new Promise(function(resolve){
		 val++;
		 resolve(val);
	 });
}

function b(val){
	return new Promise(function(resolve,reject){
		val++;
		reject(val);
	});
}



a(0)
.then(b)
.then(function(value){
	console.log('total value: '+ value);
})
.catch(function(err){
	console.log('errored @ '+ err);
});