Add method to delete tracks from playlist given positions - Fixes #14

Author: JMPerez

src/spotify-web-api.js

@@ -670,6 +670,35 @@ var SpotifyWebApi = (function() {
     };
     return _checkParamsAndPerformRequest(requestData, {}, callback);
   };
+
+  /**
+   * Remove tracks from a playlist, specifying the positions of the tracks to be removed.
+   * See [Remove Tracks from a Playlist](https://developer.spotify.com/web-api/remove-tracks-playlist/) on
+   * the Spotify Developer site for more information about the endpoint.
+   * @param {string} userId The id of the user. If you know the Spotify URI it is easy
+   * to find the user id (e.g. spotify:user:<here_is_the_user_id>:playlist:xxxx)
+   * @param {string} playlistId The id of the playlist. If you know the Spotify URI it is easy
+   * to find the playlist id (e.g. spotify:user:xxxx:playlist:<here_is_the_playlist_id>)
+   * @param {Array<number>} positions array of integers containing the positions of the tracks to remove
+   * from the playlist.
+   * @param {string} snapshotId The playlist's snapshot ID against which you want to make the changes
+   * @param {function(Object, Object)} callback An optional callback that receives 2 parameters. The first
+   * one is the error object (null if no error), and the second is the value if the request succeeded.
+   * @return {Object} Null if a callback is provided, a `Promise` object otherwise
+   */
+  Constr.prototype.removeTracksFromPlaylistInPositions = function(userId, playlistId, positions, snapshotId, callback) {
+    /*jshint camelcase: false */
+    var requestData = {
+      url: _baseUri + '/users/' + userId + '/playlists/' + playlistId + '/tracks',
+      type: 'DELETE',
+      postData: {
+        positions: positions,
+        snapshot_id: snapshotId
+      }
+    };
+    return _checkParamsAndPerformRequest(requestData, {}, callback);
+  };
+
   /**
    * Fetches an album from the Spotify catalog.
    * See [Get an Album](https://developer.spotify.com/web-api/get-album/) on

tests/js/spec/test.js

@@ -552,7 +552,7 @@
         var callback = sinon.spy();
         var api = new SpotifyWebApi();
         api.setAccessToken('<example_access_token>');
-        api.removeTracksFromPlaylistWithSnapshotId('jmperezperez', '7Kud0O2IdWLbEGgvBkW9di', [{uri: 'spotify:track:2Oehrcv4Kov0SuIgWyQY9e', position: 6}], 'AsNaPsHoTiD', callback);
+        api.removeTracksFromPlaylistWithSnapshotId('jmperezperez', '7Kud0O2IdWLbEGgvBkW9di', [{uri: 'spotify:track:2Oehrcv4Kov0SuIgWyQY9e', positions: [6]}], 'AsNaPsHoTiD', callback);
         that.requests[0].respond(200,
           {'Content-Type':'application/json'},
           ''
@@ -565,12 +565,32 @@
         expect(that.requests[0].requestBody).to.equal(JSON.stringify({
           tracks: [{
             uri: 'spotify:track:2Oehrcv4Kov0SuIgWyQY9e',
-            position: 6
+            positions: [6]
           }],
           snapshot_id: 'AsNaPsHoTiD'
         }));
       });
 
+      it('should remove tracks from a playlist specifying just their positions and snapshot id', function() {
+        var callback = sinon.spy();
+        var api = new SpotifyWebApi();
+        api.setAccessToken('<example_access_token>');
+        api.removeTracksFromPlaylistInPositions('jmperezperez', '7Kud0O2IdWLbEGgvBkW9di', [0,1,3,9], 'AsNaPsHoTiD', callback);
+        that.requests[0].respond(200,
+          {'Content-Type':'application/json'},
+          ''
+        );
+        expect(callback.calledWith(null, '')).to.be.ok;
+        expect(that.requests).to.have.length(1);
+        expect(that.requests[0].url).to.equal('https://api.spotify.com/v1/users/jmperezperez/playlists/7Kud0O2IdWLbEGgvBkW9di/tracks');
+        expect(that.requests[0].method).to.equal('DELETE');
+        expect(that.requests[0].status).to.equal(200);
+        expect(that.requests[0].requestBody).to.equal(JSON.stringify({
+          positions: [0,1,3,9],
+          snapshot_id: 'AsNaPsHoTiD'
+        }));
+      });
+
       it('should replace the tracks in a playlist', function() {
         var callback = sinon.spy();
         var api = new SpotifyWebApi();