date component init value default is now, but got null

[muziling]

1. date component init value not set in json or xml, component will default set to now, use formManager.getFormData() got value is String “null” ， not null, expect value is now or null

2. How to set date component value to null, I change initialDate () => DateTime.now(), to ()=> null , then got error

════════ (2) Exception caught by widgets library ═══════════════════════════════════════════════════
The getter 'year' was called on null.
Receiver: null
Tried calling: year