Spotify API with Mithril.js Promises

artists.js

// Use like the following:
// fetchArtistProfiles(names).then(vm.artist_profiles)

function fetchArtistProfiles (artistNames) {
  var promises = artistNames.map(function (name) {
    return fetchArtist(name)
      .then(fetchTracks)
      .then(buildProfile.curry(name))
  })
  return m.sync(promises)
}

function fetchArtist (name) {
  var artistSearchUrl = 'https://api.spotify.com/v1/search?q=' + name + '&type=artist';
  return m.request({url: artistSearchUrl, method: 'GET'}).then(function(artistResults) {
    return artistResults.artists.items[0]
  })
}

function fetchTracks (artist) {
  var artistTopTracksUrl = 'https://api.spotify.com/v1/artists/' + artist.id + '/top-tracks?country=US'
  return m.request({url: artistTopTracksUrl, method: 'GET'}).then(function(trackResults) {
    return trackResults.tracks
  })
}

function buildProfile (name, tracks) {
  var topThree = tracks.slice(0, 3)
  return { name: name, tracks: topThree }
}