Hello @juozmant ,
To use a backend function, you should import it into your document using the as follows:
import module from '<directory location>'
// Or
import { functionA, constantB } from '<directory location>'
In your case, the import statement should be:
import { saveData } from 'backend/Registration-checkuser.jsw'
This assumes that saveData is an exported function in a file located on the backend under this directory ‘backend/Registration-checkuser.jsw’.
Note: I can’t make sense of the code above or tell anything about it except that it registers some data.
Hope this helps.
Ahmad.