Server vs Client distinction

[aadamsx]

How can we tell if we are on the server or in the browser? In the Node world, we mostly just use the lack of a window object. But of course Deno has this object. What's a great, fool-proof way to tell in Deno?

I'm asking because I'm using Deno + SSR and would like to avoid the React useLayoutEffect warning like I'm getting when using Zustand: pmndrs/zustand#347 in Aleph: alephjs/aleph.js#221