How to use the kinvey-nativescript-sdk.User function in kinvey-nativescript-sdk

login: function () {
            var that = this;
            var activeUser = Kinvey.User.getActiveUser();
            if (activeUser == null) {
                Kinvey.User.loginWithMIC()
                    .then(function (user) {
                        activeUser = user;
                        that._navigateHome(activeUser);
                        console.log("user: " + JSON.stringify(user));
                    })
                    .catch(function (error) {
                        alert("An error occurred. Check your Kinvey settings.");
                        console.log("error: " + error);
                    });
            }
            else {
                this._navigateHome(activeUser);
            }
        },

login: function () {
            var that = this;
            var activeUser = Kinvey.User.getActiveUser();
            if (activeUser == null) {
                Kinvey.User.loginWithMIC()
                    .then(function (user) {
                        activeUser = user;
                        that._navigateHome(activeUser);
                        console.log("user: " + JSON.stringify(user));
                    })
                    .catch(function (error) {
                        alert("An error occurred. Check your Kinvey settings.");
                        console.log("error: " + error);
                    });
            }
            else {
                this._navigateHome(activeUser);
            }
        },

this._login = function () {
        if (Kinvey.User.getActiveUser()) {
            return Promise.resolve();
        } else {
            return Kinvey.User.login(Config.kinveyUsername, Config.kinveyPassword);
        }
    };

logout: function () {
            Kinvey.User.logout()
                .then(() => {
                    topmost().navigate({
                        moduleName: "login/login-page",
                        animated: true,
                        transition: {
                            name: "slideTop",
                            duration: 350,
                            curve: "ease"
                        }
                    });
                });
        },

this._login = function () {
        if (Kinvey.User.getActiveUser()) {
            return Promise.resolve();
        } else {
            return Kinvey.User.login(Config.kinveyUsername, Config.kinveyPassword);
        }
    };