code: func New(authToken, parentDir string, limit int,
  	updadeSearchSession func(string), triggerRender func()) *js.Object {
  	parentDirbr, ok := blob.Parse(parentDir)
  	if !ok {
  		dom.GetWindow().Alert(fmt.Sprintf("invalid parentDir blobRef: %q", parentDir))
  		return nil
  	}
  	return js.MakeWrapper(&Query{
  		ParentDir:           parentDirbr,
  		AuthToken:           authToken,
  		UpdateSearchSession: updadeSearchSession,
  		TriggerRender:       triggerRender,
  		Limit:               limit,
  	})
  }
docs: // New returns a new Query as a javascript object, of nil if parentDir is not a
  // valid blobRef.