iap.config({
    googlePublicKeyStrSandBox: googlePublicKeyStrSandBox,
    googlePublicKeyStrLive: googlePublicKeyStrLive,
    googleAccToken: googleAccToken,
    googleRefToken: googleRefToken,
    googleClientID: googleClientID,
    googleClientSecret: googleClientSecret
});

iap.setup((err) => {
    if (err) {
        full = { messageText: 'Failed: Invalid In-app purchase set up', category:'ProcessSubscriptionGoogle'}
        callback(null, full);
    } else {
        // refresh token before validating the receipt
        iap.refreshGoogleToken( function (err, response) {
            if (err) {
                full = { messageText: 'Failed: Cannot Refresh Token', category:'ProcessSubscriptionGoogle'}
                callback(null, full);
            } else {
                iap.validate(validationType, googleReceipt, (err, response) => {
                    if (err) {
                        full = { messageText: 'Failed: Invalid Receipt', category:'ProcessSubscriptionGoogle'}
                        callback(null, full);
                    } else {
                        console.log(response);
                    }
                });
            }
        })
  }
});