import { Storage , StorageType } from '../helpers/storage' ; export interface IToken { provider : string ; id_token ? : string ; access_token ? : string ; token_type ? : string ; scope ? : string ; state ? : string ; expires_in ? : string ; expires_at ? : Date ; } export interface ICode { provider : string ; code : string ; scope ? : string ; state ? : string ; } export interface IError { error : string ; state ? : string ; } /**
 * Helper for caching and managing OAuth Tokens.
 */ export class TokenStorage extends Storage < IToken > { constructor constructor ( storageType = StorageType . LocalStorage ) { super ( 'OAuth2Tokens' , storageType ) ; } /**
     * Compute the expiration date based on the expires_in field in a OAuth token.
     */ static setExpiry ( token ) { let expire = seconds => seconds == null ? null : new Date ( new Date ( ) . getTime ( ) + ~ ~ seconds * 1000 ) ; if ( ! ( token == null ) && token . expires_at == null ) { token . expires_at = expire ( token . expires_in ) ; } } /**
     * Check if an OAuth token has expired.
     */ static hasExpired ( token ) { if ( token == null ) { return true ; } if ( token . expires_at == null ) { return false ; } else { token . expires_at = token . expires_at instanceof Date ? token . expires_at : new Date ( token . expires_at as any ) ; return token . expires_at . getTime ( ) - new Date ( ) . getTime ( ) < 0 ; } } param { string } provider return { object } get ( provider ) { let token = super . get ( provider ) ; if ( token == null ) { return token ; } let expired = TokenStorage . hasExpired ( token ) ; if ( expired ) { super . delete ( provider ) ; return null ; } else { return token ; } } param { string } provider param { object } config see IToken .
     *  return { object } add ( provider , value ) { value . provider = provider ; TokenStorage . setExpiry ( value ) ; return super . set ( provider , value ) ; } }