Will all widges support nodejs fully?

Site and Services
1

When will data loading, saving, exporting can be used with nodejs?

2

Webix can be used with any REST, so it works perfectly with NodeJs

http://webix.com/blog/using-webix-with-nodejs/

3

http://docs.webix.com/datatable__export.html

no nodejs in this document.

4

Yep, there is no nodejs specific code here yet.
Still you can use online version, that doesn’t require any server at all.