Pass objects into Pug mixins for default arguments

index.pug

include mixin.pug

+navigation_li('Anchor text here', {
  a_class: 'c-main-navigation__link',
  li_class: 'active'
})

+navigation_li('More anchor text here', {
  a_class: 'c-main-navigation__link'
})

mixin.pug

mixin navigation_li(name, attr)

  - var li_class = attr.li_class || ''
  - var a_class = attr.a_class || ''
  
  li(class=li_class)
    a(class=a_class)= name