How to accept, pass variables to Slim::Template.new("").render()?

Question

gulp.js

How to pass and receive variables from Slim::Template.new("").render()
Using slim in conjunction with gulp
An example of what you need
index.slim

== Slim::Template.new('partitial.slim', :pretty => true).render('здесь надо задать переменную')

partial.slim
а здесь ее надо как-то принять и вывести
PS. I'm trying to hang a class on the header, depending on which page it is added to.