4. useSWR() I

SWR is a popular library of data fetching.

Let's try to implement the basic usage by ourselves.

import React from 'react'function App() {  const { data, error } = useSWR('/api', fetcher)  if (error) return <div>failed</div>  if (!data) return <div>loading</div>  return <div>succeeded</div>}

1. this is not to replicate the true implementation of useSWR()
2. The first argument key is for deduplication, we can safely ignore it for now