How to add a class to only the first tag in a jade-generated list?

Question

Pug

Good afternoon!
There is a jade code:

nav.main-nav
      each val in ["Journal", "About", "Work", "Contact"]
        a(href="/").main-nav__item= val

How do I add a separate class to just the first link using jade?
Is it possible at all or is it easier to do with scripts in this case?
Thank you for your attention.

Answer 1

each val, index in ["Journal", "About", "Work", "Contact"]
  - var class = 'main-nav__item';
  - class += index === 0 ? ' special' : ''
  a(href="/", class="#{class}")= val

Answer 2

nav.main-nav
  - var first = true;
  each val in ["Journal", "About", "Work", "Contact"]
    - var cn = '';
    - if(first) cn = 'foo';
    a(href="/", class = cn).main-nav__item= val
    - first = false;