Array of promises

array_promise.js

function fetchUserDetails(arr) {
  return arr.reduce(function(promise, elem) {
      return promise.then(function() {
          return db.getUser(email).done(function(res) {
              logger.log(res);
          });
      });
  }, Promise.resolve());
}

var arrayOfEmailAddys = [];

fetchUserDetails(arrayOfEmailAddys).then(function() {
    console.log('all done');
});