" https://vi.stackexchange.com/questions/454/whats-the-simplest-way-to-strip-trailing-whitespace-from-all-lines-in-a-file
function! Preserve(command)
  " Preparation: save window state
  let l:saved_winview = winsaveview()
  " Run the command:
  execute a:command
  " Clean up: restore previous window position
  call winrestview(l:saved_winview)
endfunction

nnoremap <unique> <silent> <Leader>ws  :call Preserve("%s/\\s\\+$//e")<CR>
xnoremap <unique> <silent> <Leader>ws  :call Preserve("%s/\\s\\+$//e")<CR>