command! -nargs=* JSLint call JSLint(<f-args>)
  " @param boolean interact: 1 to prompt before lint.
  " @param string options: custom options for running JSLint. in JSON string, ex: '{"onevar":false}'
  fun! JSLint(...)
    if ! executable('jslint')
      echohl WarningMsg | echoerr "jslint command not found." | echohl None
      return
    endif
    let input    = expand('%')
    let interact = a:0 > 0 ? a:1 : 0
    let options  = a:0 > 1 ? a:2 : ''

    if &modified
      echomsg 'No write since last change, write before lint? (y/n) '
      let ans = getchar()
      if nr2char(ans) == 'y' | w
      elseif nr2char(ans) != 'n' | redraw! | echomsg 'JSLint aborted.' | return
      endif
    endif

    if &filetype == 'javascript'
      let cmd = 'jslint ' . input . ' ' . options
      if interact
        echomsg 'JSLint ' . input . '? (y/n) ' | redraw
        let yes = getchar()
        if nr2char(yes) == 'y'
          return DoJSLint(cmd, input)
        else
          redraw!
          echomsg 'JSLint aborted.'
          return
        endif
      else
        return DoJSLint(cmd, input)
      endif
    else
      echohl WarningMsg | echomsg "Unsupported filetype." | echohl None
    endif
  endf

  fun! DoJSLint(cmd, file)
    echomsg "JSLint in progress..."
    let ret = system(a:cmd)
    if v:shell_error
      cexpr ret
      if len(getqflist()) > 0
        QFix!<CR>
      endif
    else
      redraw
      echomsg "No problems found in " . a:file
      return
    endif
  endf