Will all widges support nodejs fully?

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

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

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

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

no nodejs in this document.

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