Jade + Bootstrap Pagination Mixin

pagination.jade

//- Pagination mixin
//- ----------------
//- numPages = # links to serve up
//- numButtons = # of "side" buttons that will be present. 
//- 2 numButtons will result in | << | 1 | 2 |>3<| 4 | 5 | >> | 
//- curr = current page
//- base = base url before num
//- start at page 1
//- 
//- Example:
//- pagination(10, 3, 4, '/fda/')
//- Yields: | « | 1 | 2 | 3 |>4<| 5 | 6 | 7 | » |
//- « = /fda/2, 3 = /fda/3, 4 = #, .. 7 = /fda/7, » = /fda/8

mixin pagination(numPages, numButtons, curr, base)
  - let start  = 1
  - numPages   = numPages   || 10
  - numButtons = numButtons || 4
  - curr       = curr       || 1
  - base       = base       || '#'

  - let highestFirstPage = numPages - (numButtons * 2) - 1
  - let smallestLastPage = start + (numButtons * 2) 

  - let firstButton = Math.min(highestFirstPage, Math.max(start, (curr - numButtons)))
  - let lastButton = Math.max(smallestLastPage, Math.min(numPages, (curr + numButtons)))
    

  ul.pagination
    - if(curr === start) 
      li.disabled
        a Prev
    - else
      li
        a(href=base + (curr - 1)) Prev

    - for(let i = firstButton; i <= lastButton; i++) {
      - if(curr === i)
        li.active
          a(href=base + i) #{i}
      - else
        li
          a(href=base + i) #{i}
    - }

    - if(curr === numPages)
      li.disabled
        a Next
    - else
      li
        a(href=base + (curr + 1)) Next