Function verifyRefreshToken

verifyRefreshToken(
refreshToken: undefined | string,
userModel: any,
): Promise<any>
Verifies a refresh token and checks its validity against the user's stored tokens.
Parameters
- refreshToken: undefined | string
  The refresh token to verify.
- userModel: any
  The user model (should support findById and save).
Returns Promise<any>
A Promise that resolves with the user if valid, or rejects with an error message.
- Defined in auth/tokenService.ts:61