Good sources about the basics (and some advanced topics) for XSJS and native HANA development in general you find in
- Introduction to Software Development on SAP HANA
- Next Steps in Software Development on SAP HANA
- Software Development on SAP HANA (Delta SPS 09, Repeat)
- http://help.sap.com/hana/SAP_HANA_Interactive_Education_SHINE_en.pdf
But please consider that these documents are covering the XS classic things. With XS Advanced (available since SPS11) there will be some changes not covered in that documents. For that specific documents and courses exists.
Best Regards,
Florian