gistfile1.txt

const basename = require('basename');
//const glob = require('glob');
const Promise = require('bluebird');

const globAsync = Promise.promisify(require('glob'));

const dir = 'a';

function galleryListPromise() {
  return Promise.try( () => {
      return globAsync("gallery/*/", {})
    }
  )
  .then( (dirs) => {
      const realdirs = {};
      dirs.map( x => realdirs[basename(x)] = 1 );
      return realdirs;
    }
  );
}

function imageListPromise(galleryList) {
  return Promise.try( () => {
    if (galleryList[dir] === 1) {
      return globAsync(`gallery/${dir}/*jpg`, {});
    } else {
      return [];
    }
  })
  .then( (imagelist) => {
      return [galleryList, imagelist];
    }
  );
}

galleryListPromise()
  .then( (galleryList) => {
    return imageListPromise(galleryList).then( (imageList) => {
        console.log(imageList);
    });
});