interface TokenInstance { getToken: () => string setToken: (token: string) => void getAdditionalDataForTokenValidation: (key: string) => any } const tokenKey = 'token' class LocalStorageToken implements TokenInstance { getToken = () => { return localStorage.getItem(tokenKey) || '' } setToken = (token: string) => { localStorage.setItem(tokenKey, token) } getAdditionalDataForTokenValidation = (key: string) => { return localStorage.getItem(key) } } export { LocalStorageToken, TokenInstance }