call NERDTreeAddKeyMap({ \ 'key': 'w', \ 'callback': 'NERDTreeToggleWidth', \ 'quickhelpText': 'Toggle window width' }) function! NERDTreeToggleWidth() let l:maxi = 0 for l:z in range(1, line("$")) let l:aktlen = len(getline(l:z)) if l:aktlen > l:maxi let l:maxi = l:aktlen endif endfor exe "vertical resize " . (l:maxi == winwidth(".") ? g:NERDTreeWinSize : l:maxi) endfunction