promise example

function A() { return new Promise(function(resolve, reject) { setTimeout(function () { reject(1000); }, 1000); }); } function B() { return new Promise(function(resolve, reject) { setTimeout(function () { reject(2000); }, 2000); }); } function C() { return new Promise(function(resolve, reject) { setTimeout(function () { reject(3000); }, 3000); }); } function D() { return new Promise(function(resolve, reject) { setTimeout(function () { reject(4000); }, 4000); }); }

function ABCD() { var workqueue = [A, B, C, D]; return Promise.all(workqueue.map(function(work) { return work(); })) } ABCD().then(function(result) { console.log("result: " + result); }).catch(function(err) { console.log("err: " + err); });