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

login() {
        let activeUser = Kinvey.User.getActiveUser();
        if (activeUser == null) {
            Kinvey.User.loginWithMIC()
                .then((user: Kinvey.User) => {
                    activeUser = user;
                    this.navigateHome(activeUser);
                    console.log("user: " + JSON.stringify(user));
                })
                .catch((error: Kinvey.BaseError) => {
                    alert("An error occurred. Check your Kinvey settings.");
                    console.log("error: " + error);
                });
        } else {
            this.navigateHome(activeUser);
        }
    }

login() {
        let activeUser = Kinvey.User.getActiveUser();
        if (activeUser == null) {
            Kinvey.User.loginWithMIC()
                .then((user: Kinvey.User) => {
                    activeUser = user;
                    this.navigateHome(activeUser);
                    console.log("user: " + JSON.stringify(user));
                })
                .catch((error: Kinvey.BaseError) => {
                    alert("An error occurred. Check your Kinvey settings.");
                    console.log("error: " + error);
                });
        } else {
            this.navigateHome(activeUser);
        }
    }

private login(): Promise {
        if (!!Kinvey.User.getActiveUser()) {
            return Promise.resolve();
        } else {
            return Kinvey.User.login(Config.kinveyUsername, Config.kinveyPassword);
        }
    }

static signup(registrationForm: RegistrationForm): Promise {
        return Kinvey.User.signup({
            username: registrationForm.email.toLowerCase(),
            password: registrationForm.password,
            givenName: registrationForm.givenName,
            familyName: registrationForm.familyName,
            email: registrationForm.email,
            gender: registrationForm.gender,
            dateOfBirth: registrationForm.dateOfBirth
        });
    }
}

static signup(registrationForm: RegistrationForm): Promise {
        return Kinvey.User.signup({
            username: registrationForm.email.toLowerCase(),
            password: registrationForm.password,
            givenName: registrationForm.givenName,
            familyName: registrationForm.familyName,
            email: registrationForm.email,
            gender: registrationForm.gender,
            dateOfBirth: registrationForm.dateOfBirth
        });
    }
}

private login(): Promise {
        if (!!Kinvey.User.getActiveUser()) {
            return Promise.resolve();
        } else {
            return Kinvey.User.login(Config.kinveyUsername, Config.kinveyPassword);
        }
    }