Function getCacheControlHeader

packages/next/src/server/lib/cache-control.ts:17–35

({
  revalidate,
  expire,
}: CacheControl)

}

export function getCacheControlHeader({
  revalidate,
  expire,
}: CacheControl): string {
  const swrHeader =
    typeof revalidate === 'number' &&
    expire !== undefined &&
    revalidate < expire
      ? `, stale-while-revalidate=${expire - revalidate}`
      : ''

  if (revalidate === 0) {
    return 'private, no-cache, no-store, max-age=0, must-revalidate'
  } else if (typeof revalidate === 'number') {
    return `s-maxage=${revalidate}${swrHeader}`
  }

  return `s-maxage=${CACHE_ONE_YEAR_SECONDS}${swrHeader}`
}