function syncRepeatPlaylist(playlist) {
    /*
    Gets all of the repeat buttons.
    */
    var repeatButtons = document.getElementsByClassName("amplitude-repeat");

    /*
    Iterate over all of the repeat buttons
    */
    for (var i = 0; i < repeatButtons.length; i++) {
      /*
      Ensure that the repeat button belongs to matches the
      playlist we are syncing the state for.
      */
      if (repeatButtons[i].getAttribute("data-amplitude-playlist") == playlist) {
        /*
        If the state of the playlist is shuffled on, true, then
        we add the 'amplitude-repeat-on' class and remove the
        'amplitude-repeat-off' class. If the player is not shuffled
        then we do the opposite.
        */
        if (_config2.default.playlists[playlist].repeat) {
          repeatButtons[i].classList.add("amplitude-repeat-on");
          repeatButtons[i].classList.remove("amplitude-repeat-off");
        } else {
          repeatButtons[i].classList.add("amplitude-repeat-off");
          repeatButtons[i].classList.remove("amplitude-repeat-on");
        }
      }
    }
  }
Syncs repeat for all of the playlist repeat buttons. Users
can apply styles to the `amplitude-repeat-on` and `amplitude-repeat-off`
classes. They repreent the state of the playlist in the player.