EuiBreadcrumbs breaks SSR

[pugnascotia]

EuiBreadcrumbs directly references window without any guards. I found this because I tried upgrading EUI in next-eui-starter, and rendering the index page broke.

Replicate in the starter repo with:

• nvm use 14 (the next step upgrades a dependency that requires node >= 13.7)
• yarn upgrade --latest
• yarn dev
• Visit http://localhost:3000

[IvanovRoman]

Solved for me:
import dynamic from 'next/dynamic';

const EuiHeaderBreadcrumbs = dynamic(
() => import('@elastic/eui').then(mod => mod.EuiHeaderBreadcrumbs),
{
ssr: false,
}
);

[mytototo]

It looks like EuiCollapsibleNav breaks SSR as well...

[thompsongl]

At present, EUI doesn't have an official support strategy for SSR. We'd like to get to a place where we do, but it's not currently prioritized on the roadmap.

We'll fix (and happily accept PRs for) errors like these, but until there is a better testing framework in place for various app environments, they will likely continue to be one-off fixes.