How to chunk Promises with Bluebird

chunked_promises.js

const Promise = require('bluebird');

const stocks = ['aapl', 'googl', 'f', 'gm'];

function getThings(things) {
  // DOCS: http://bluebirdjs.com/docs/api/promise.map.html
  return Promise.map(things, thing => Promise.resolve(thing), { concurrency: 2 });
}

getThings(stocks);