Function getSignedCookieValue

getSignedCookieValue(
    cookie: string | readonly string[] | null | undefined,
    name: string,
    secret: string | BufferSource,
): Promise<string | undefined>
Returns the value of a cookie that was signed with a secret.
Parameters
- cookie: string | readonly string[] | null | undefined
  The Cookie header value or Document.cookie.
- name: string
  The name of a cookie to retrieve.
- secret: string | BufferSource
  The signing secret key.
Returns Promise<string | undefined>
The cookie value, or undefined if there's no cookie with the given name or signature verification has failed.