"simulates" an async function with Promises

simAsync.js

// requires https://gist.github.com/toddzebert/b4465de41b0f8d317d7a685604983c36
var simAsync = function(fulfillment, rejection) {
  return new Promise( (resolve, reject) => {
    const delay = randInt(400, 200);
    setTimeout(() => { resolve(fulfillment()); }, delay);
  });
};