Override serialize not to serialize an entry

[mebibou]

One of the widget I use is to configure a new widget, where I can select the type and some data, once save I add a new empty widget ( so there is always one empty for new). I want to override the serialize option not to save the empty one, but currently doing serialize: function() { return; } will save null in the storage. I've tried different variation but it doesn't look like it is possible to simply not serialize one of the entries.