gistfile1.js

deleteVersion: function () {
  var version = this.get('version'),
      arrangedObjects = ContentManager.versionsController.get('arrangedObjects'),
      idx = arrangedObjects.indexOf(version);
  version.destroy();
  version.commitRecord();
  this.invokeLater(function () {
    var object, test;
    
    // start from the previous item
    idx = idx - 1;
    
    var indices = SC.IndexSet.create().addEach(arrangedObjects.map(function(item, index) {
      return !item['isGroup'] ? index : null;
    }));
    
    // easy, previous object is selectable
    if (indices.contains(idx)) {
      object = arrangedObjects.objectAt(idx);
    }
    // previous object not in range
    // check next object ahead for next idx
    // will only return true if it was in same group
    else if (indices.contains(idx + 1)) {
      object = arrangedObjects.objectAt(idx + 1);
    }
    // prefer indices from previous groups
    else if ((test = indices.indexBefore(idx)) > -1) {
      object = arrangedObjects.objectAt(test);
    }
    // check for indices after, this is our last resort
    else if ((test = indices.indexAfter(idx)) > -1) {
      object = arrangedObjects.objectAt(test);
    }
    // nothing selectable
    else {
      object = null;
    }
    
    ContentManager.versionsController.selectObject(object);
  });
  return YES;
}