nav-menu cache using javascript

[tazotodua]

hello.
as we know, caching of navigation menus cause to loose "current-item" classes...
but there could be a solution:
it will be good, if nav-menu could be cached, but WP-CORE should contain something like this, to set "current-item" classes:
​http://wordpress.stackexchange.com/a/232574/33667

[SergeyBiryukov]

Related: #36225

[tazotodua]

i've updated the answer on that link.