spotify-save-all-in-playlist.js

/*
 * This Script adds every song in the playlist you're currently
 * viewing at https://play.spotify.com to "Your Music". 
 * 
 * Open your browser console and paste this script to run it.
 */
(function() {
  
  // Get the ID of the playlist you're currently viewing at https://play.spotify.com.
  var playlistFrameId = document.querySelector('iframe[id^=collection]').getAttribute('id');
  
  // Get the child window that playlist is being displayed in.
  var playlistFrame = window[playlistFrameId].contentWindow;
  
  // Get all the + or √ buttons
  var saveButtons = playlistFrame.document.querySelectorAll('[data-ta-id="track-add-button"]');
  
  // filter out the √ buttons (delete the "!" to filter out the + buttons instead).
  [].slice.call(saveButtons).filter(function(button) {
    return !button.parentNode.parentNode.matches('.added');
  })
  
  // Loop over the remaining buttons.
  .forEach(function(button) {
    
    // and click them.
    button.click();

  });

}());