client/js/utils/PlaylistUtils.js
/**
   * @param {string} playlistId The unique id of the playlist object
   * @param {integer} songId The unique id of the song object
   */
@param {string} playlistId The unique id of the playlist object
@param {integer} songId The unique id of the song object
@param { string } playlistId The unique id of the playlist object @param { integer } songId The unique id of the song object
createPlaylistSong(playlistId, songId, playlistOrder) {
    let playlistSong = {
      'playlist_id': playlistId,
      'song_id': songId,
      'playlist_order': playlistOrder
    };
    API.create('playlistSongs', [playlistSong])
      .then((newPlaylistSongs) => {
        ServerActionCreators.receiveCreatedPlaylistSongs(newPlaylistSongs);
      })
      .catch((error) => {
        console.log(error);
      });
  }
createPlaylistSong ( playlistId , songId , playlistOrder ) { let playlistSong = { 'playlist_id' : playlistId , 'song_id' : songId , 'playlist_order' : playlistOrder } ; API . create ( 'playlistSongs' , [ playlistSong ] ) . then ( ( newPlaylistSongs ) => { ServerActionCreators . receiveCreatedPlaylistSongs ( newPlaylistSongs ) ; } ) . catch ( ( error ) => { console . log ( error ) ; } ) ; }
@param {string} playlistId The unique id of the playlist object
 @param {integer} songId The unique id of the song object
@param { string } playlistId The unique id of the playlist object @param { integer } songId The unique id of the song object