split a cookie string into their parts, and return selected key

get_cookie.server.ts

export function getCookie(cookieHeader: string | null, key: string): string | undefined {
  if (!cookieHeader) {
    return
  }

  const parts = cookieHeader.split(";").map(kv => {
    let t = kv.trim()
    return t.split("=")
  })

  return parts.find(([k, v]) => k === key)?.[1]
}