code: function haveDifferentKeys(object1, object2) {
    var keys1 = Object.keys(object1);
    var keys2 = Object.keys(object2);
  
    if (keys1.length !== keys2.length) {
      return true;
    }
  
    return !keys1.every(function existsInKeys2 (key) {
      return keys2.indexOf(key) !== -1;
    });
  }
docs: function filterCursors(props) { var cursors = {};  for (var name in props) { var potentialCursor = props[name];  if (isCursor(potentialCursor)) { cursors[name] = potentialCursor; } }  return cursors; }