Issue in sending payment via ( paypal cordova mobile sdk) in ionic

I have integrated paypal cordova mobile sdk for payment . But getting Json error in cdv-plugin-paypal-mobile-sdk.js in following code snippet ,while trying to make payment

PayPalMobile.prototype.init = function(clientIdsForEnvironments, completionCallback) {
 var failureCallback = function(error) {
    console.log(error);
  };

In controller , initializing the payment on button click as follows -

 $scope.sendMoney = function ()
    {
        PaypalService.initPaymentUI().then(function () { PaypalService.makePayment(50, "Total").then();       });
    }

PaypalService is implemented as -

    angular.module('starter.PaypalService', ['starter.Constants'])
.factory('PaypalService', ['$q', '$ionicPlatform','Constants', '$filter', '$timeout', function ($q, $ionicPlatform, Constants, $filter, $timeout) {



    var init_defer;
    /**
     * Service object
     * @type object
     */
    var service = {
        initPaymentUI: initPaymentUI,
        createPayment: createPayment,
        configuration: configuration,
        onPayPalMobileInit: onPayPalMobileInit,
        makePayment: makePayment
    };


    /**
     * @ngdoc method
     * @name initPaymentUI
     * @methodOf app.PaypalService
     * @description
     * Inits the payapl ui with certain envs.
     *
     *
     * @returns {object} Promise paypal ui init done
     */
    function initPaymentUI() {

        init_defer = $q.defer();
        $ionicPlatform.ready().then(function () {

            var clientIDs = {
                "PayPalEnvironmentProduction": Constants.payPalProductionId,
                "PayPalEnvironmentSandbox": Constants.payPalSandboxId
            };
            PayPalMobile.init(clientIDs, onPayPalMobileInit);
        });

        return init_defer.promise;

    }


    /**
     * @ngdoc method
     * @name createPayment
     * @methodOf app.PaypalService
     * @param {string|number} total total sum. Pattern 12.23
     * @param {string} name name of the item in paypal
     * @description
     * Creates a paypal payment object
     *
     *
     * @returns {object} PayPalPaymentObject
     */
    function createPayment(total, name) {

        // "Sale  == >  immediate payment
        // "Auth" for payment authorization only, to be captured separately at a later time.
        // "Order" for taking an order, with authorization and capture to be done separately at a later time.
        var payment = new PayPalPayment("" + total, "INR", "" + name, "Sale");
        return payment;
    }
    /**
     * @ngdoc method
     * @name configuration
     * @methodOf app.PaypalService
     * @description
     * Helper to create a paypal configuration object
     *
     *
     * @returns {object} PayPal configuration
     */
    function configuration() {
        // for more options see `paypal-mobile-js-helper.js`
        var config = new PayPalConfiguration({merchantName: Constants.payPalShopName, merchantPrivacyPolicyURL: Constants.payPalMerchantPrivacyPolicyURL, merchantUserAgreementURL: Constants.payPalMerchantUserAgreementURL});
        return config;
    }

    function onPayPalMobileInit() {
        $ionicPlatform.ready().then(function () {
            // must be called
            // use PayPalEnvironmentNoNetwork mode to get look and feel of the flow
            PayPalMobile.prepareToRender(Constants.payPalEnv, configuration(), function () {

                $timeout(function () {
                    init_defer.resolve();
                });

            });
        });
    }

    /**
     * @ngdoc method
     * @name makePayment
     * @methodOf app.PaypalService
     * @param {string|number} total total sum. Pattern 12.23
     * @param {string} name name of the item in paypal
     * @description
     * Performs a paypal single payment
     *
     *
     * @returns {object} Promise gets resolved on successful payment, rejected on error
     */
    function makePayment(total, name) {


        var defer = $q.defer();
        total = $filter('number')(total, 2);
        $ionicPlatform.ready().then(function () {
            PayPalMobile.renderSinglePaymentUI(createPayment(total, name), function (result) {
                $timeout(function () {
                    defer.resolve(result);
                });
            }, function (error) {
                $timeout(function () {
                    defer.reject(error);
                });
            });
        });

        return defer.promise;
    }

    return service;
}]);

Any help will be deeply appreciated.