Run Multi Promise as Serial

serialPromise.js

var Promise = require('bluebird');

function getP (t) {
  return new Promise((resolve, reject) => {
    console.time(t);
    setTimeout(() => {
      console.log('\none Promise', t);
      console.timeEnd(t);
      return resolve();
    }, t);
  });
}

let qs = [];
for(var i = 0; i <= 3; i++ ) {
  qs.push(Math.floor(Math.random() * 2000));
}

console.log('qs:', qs);

let doAll = Promise.resolve(qs).map(getP, {concurrency: 1});

doAll.then(() => {
  console.log('all Done');
});