Google does not index my ng2 site without prerendering.

There will be always limits for search engines on interpreting js.

That's interesting. I previously researched this with regard to React apps, and the tenor was that server-side rendering was no longer required in order to get indexed by Google.

Google itself has this to say:

https://webmasters.googleblog.com/2014/05/understanding-web-...

Have you tried to figure out the cause using Search Console?

I have also encountered an Angular 1 app in the wild that was indexed by Google, but there are limits to the ability of their crawler - it apparently didn't follow through to other pages.