How to use coalesce with select in gremlin?

Question

Query

g.V().
has('id', 1).
out('follows').
as('x').
out('knows').
as('y').
project('Name').
by(select('x').by('name'))

Here I want to use coalesce in the projection because there are vertices where name property does not exist.

I tried this but it doesn't work,

by(coalesce(select('x').by('name'), constant('null'))

Answer 1

Change the by to values and it should work:

g.V().
  has('id', 1).
  out('follows').
  as('x').
  out('knows').
  as('y').
  project('Name').
    by(coalesce(select('x').values('name'), constant('null')))