Is it possible to know whether a page is using SSR or SSG in _app.getInitialProps?

[Vadorequest]

In _app.getInitialProps, it'd be useful to know wether the page is using SSR or SSG, in order to perform some automated processing.

One example would be to bypass most of the work related to SSR pages, when building SSG pages. See #10909 (reply in thread)

I'm thinking the props provided to getInitialProps could contain such information.

[andreas1327250]

I solved it by setting a boolean flag on the page itself (like you would define getInitialProps)

MyPage.hasStaticProps = true

[Vadorequest]

It's similar to #10949 (reply in thread)

I'm not a fan, it's easy to make a mistake when removing SSG from a page (keep the boolean on while using SSR), or forgetting to add it.

I'm looking for a more robust way of doing things, automated.