JsonWebToken usage 'generate', 'verify' and 'refresh' token

jwt.ts

import jwt from 'jsonwebtoken';

interface payload {
  data: object;
}

type GenerateToken = (data: object) => string;
type VerifyToken = (
  token: string
) => {
  isValid: boolean;
  data?: object;
  message?: string;
};
type RefreshToken = (
  token: string
) => {
  isValid: boolean;
  token?: string;
  message?: string;
};

const issuer = 'BIG_USER_SYSTEM';
const subject = 'some@user.com';
const audience = 'example.com';
const SIGNATURE_KEY = process.env.SIGNATURE_KEY!;

const signOptions = {
  issuer,
  subject,
  audience,
  expiresIn: '1h',
  algorithm: 'HS256'
};

export const generateToken: GenerateToken = (data) =>
  jwt.sign({ data } as payload, SIGNATURE_KEY, signOptions);

export const verifyToken: VerifyToken = (token) => {
  try {
    const { data } = jwt.verify(token, SIGNATURE_KEY, signOptions) as payload;
    return {
      isValid: true,
      data
    };
  } catch (err) {
    return {
      isValid: false,
      message: err.message
    };
  }
};

export const refreshToken: RefreshToken = (token) => {
  const { isValid, data, message } = verifyToken(token);
  return isValid
    ? {
        isValid,
        token: generateToken(data!)
      }
    : {
        isValid,
        message
      };
};