toJson method
JSON으로 변환
Implementation
Map<String, dynamic> toJson() => {
'provider': provider.name,
'user': user.toJson(),
if (accessToken != null) 'accessToken': accessToken,
if (refreshToken != null) 'refreshToken': refreshToken,
if (idToken != null) 'idToken': idToken,
if (expiresAt != null) 'expiresAt': expiresAt!.toIso8601String(),
if (serverToken != null) 'serverToken': serverToken,
'savedAt': savedAt.toIso8601String(),
};