Promise.all.js

var promises = ['foo', 'bar'].map(id => {
  return new Promise(resolve => {
    couchDb.get(
      id,
      function (error, data) {
        // error handling
        return resolve(data);
      }
    )
  });
});

Promise.all(promises)
  .then(data => {
    console.log(data);
  })
  .catch(error => {
      console.log(error);
    }
  );