How to use the node-fetch-npm.isRedirect function in node-fetch-npm

!isStream && (
              res.status === 408 || // Request Timeout
              res.status === 420 || // Enhance Your Calm (usually Twitter rate-limit)
              res.status === 429 || // Too Many Requests ("standard" rate-limiting)
              res.status >= 500 // Assume server errors are momentary hiccups
            )

          if (isRetriable) {
            if (typeof opts.onRetry === 'function') {
              opts.onRetry(res)
            }

            return retryHandler(res)
          }

          if (!fetch.isRedirect(res.status) || opts.redirect === 'manual') {
            return res
          }

          // handle redirects - matches behavior of npm-fetch: https://github.com/bitinn/node-fetch
          if (opts.redirect === 'error') {
            const err = new Error(`redirect mode is set to error: ${uri}`)
            err.code = 'ENOREDIRECT'
            throw err
          }

          if (!res.headers.get('location')) {
            const err = new Error(`redirect location header missing at: ${uri}`)
            err.code = 'EINVALIDREDIRECT'
            throw err
          }