Detecting server vs client in NextJS application

There are couple of ways we can detect the NextJS code running on client vs server.

1. Using process.browser

process.browser return true on client and return undefind on server side.
So we can write the following code.

let isServer = (process.browser)? false : true;

2. Checking window object

window object is only available on the browser, so we can do the following

let isServer = (typeof window === 'undefined')? false : true;