A Jade HTML mixin to render Bootstrap pagination

pagination.jade

//- Pagination mixin
//- ----------------
//- start=# to start pagination at
//- numpages=# links to serve up
//- base=base url before num
//-
//- Example:
//- pagination(1,5,4,'/disc/','?keywords=test')
//- Yields: | < | 3 | 4 | 5 | 6 | 7 | > |
//- « = /disc/2, 3 = /disc/3, 4 = #, .. 7 = /disc/7, » = /disc/8
//- querystring will be added to any link if defined
mixin pagination(start, numpages, curr, base, querystring)
  - var querystring = querystring?querystring:''
  - var curr = typeof curr=="string"?parseInt(curr, 10):curr
  if(numpages > 1)
    nav.pull-right
      ul.pagination
        - if(curr > 1)
          li
            a(href="#{base}#{curr - 1}#{querystring}")
              i.fa.fa-angle-left
        - else
          li.disabled
            a(href="#")
              i.fa.fa-angle-left
        - var lower = curr-2; if(curr >= (numpages - 2)){lower = (numpages - 4)}
        - var upper = curr+2; if(upper < 5 && numpages >= 5){upper = 5}
        - for(var i = lower; i <= upper; ++i)
          - if (i <= numpages && i > 0)
            - if (i !== curr)
              li
                a(href="#{base}#{i}#{querystring}")=i
            - else
              li.active
                a(href="#{base}#{i}#{querystring}")=i
        - if(curr < numpages)
          li
            a(href="#{base}#{curr + 1}#{querystring}")
              i.fa.fa-angle-right
        - else
          li.disabled
            a(href="#")
              i.fa.fa-angle-right