Vimperator code to add `closealltoright` and `closealltoleft` commands (and corresponding keybindings). Add to `~/.vimperatorrc`

close_all_to_right_or_left.vimperator

js <<EOF

closeAllToRight = function () {
    var current = tabs.getTab();
    var currentIx = tabs.index(current);
    var nexttab = current.nextElementSibling;
    var N = tabs.count;
    var numToClose = N - (currentIx + 1);
    tabs.remove(nexttab, numToClose);
}

closeAllToLeft = function () {
    var current = tabs.getTab();
    var currentIx = tabs.index(current);
    var firsttab = tabs.getTab(0);
    var N = tabs.count;
    var numToClose = currentIx;
    tabs.remove(firsttab, numToClose);
}

EOF

" close tabs to left
map x< :js closeAllToLeft()<CR>
" close tabs to right
map x> :js closeAllToRight()<CR>

command! closealltoright :js closeAllToRight()
command! closealltoleft :js closeAllToLeft()