Best practice for isLoading. What different with isValidating?

[terrierscript]

In SWR documentation, I cannot found about isLoading explicitly.

This page show like this

isLoading: !error && !data,

Similirary, [quick start] section show like this
https://swr.vercel.app/getting-started#quick-start

 if (error) return <div>failed to load</div>
 if (!data) return <div>loading...</div>

And isValidating is explained like this

isValidating: if there's a request or revalidation loading

Question1: What is best practice for isLoading? Is this isLoading: !error && !data ?
Question2: What is isValidating use case?

[sergiodxa]

Loading only happens once, when you don’t have data or error, this is when it’s the first time you use a key.

Validation can happen more than once, when you already have data or error and SWR is calling your fetcher again to update it.

I usually use Suspense for loading, but you can check if if you have data or error as in the examples (I like more the second one checking for error first and !data later).

You should use isValidating if you want to tell your users your data is being updated.