JST Folds

let b:fold_levels = {}
function! JST_Folds(lnum)
  let line = getline(a:lnum)
  if line =~ '^describe'
    return '0'
  elseif line =~ '^\s\+\(describe\|it\)'
    let lead = matchstr(line, '^\s\+')
    let b:fold_levels[lead] = lead
    return 'a1'
  elseif line =~ '^\s\+}\s*)\s*;'
    let lead = matchstr(line, '^\s\+')
    if has_key(b:fold_levels, lead)
      call remove(b:fold_levels, lead)
      return 's1'
    else
      return '='
    endif
  else
    return '='
  endif
endfunction

set fdm=expr
set fde=JST_Folds(v:lnum)