How to check key for value before revalidate

[daveteu]

currently in page I use this

const { data, error, mutate } = useSWR('/api/', fetcher)

in child component I use this so I can get the values

const { data, error, mutate } useSWR('/api', fetcher, { revalidateOnMount: false}

Is there anyway I can access the current key value, check if the key is "fetched before" before fetching?

pseudo code
const { data, error, mutate } = useSWR('/api', (currentkeydata) => fetcher(check if currentkeydata exist before fetch))

[sergiodxa]

You can import the internal cache doing:

import { cache } from "swr";

And then read a value using cache.get(key).

However, I'm not sure what do you plan to achieve, do you want to effectively prevent SWR from revalidating your data? If so, why use SWR?