createToken does not work with individual elements

[rezmag-wontok]

If I create one card element and pass it onto createToken it works like charm but when I create three individual elements of Card Number, Expiry and Cvc, and pass each to createToken, it fails. The response from the server is:

{
"error": {
"code": "parameter_missing",
"doc_url": "https://stripe.com/docs/error-codes/parameter-missing",
"message": "Missing required param: card[exp_month].",
"param": "card[exp_month]",
"type": "invalid_request_error"
}
}

and the request is clearly missing all the values required to create a token:

{
"card": {
"name": "Rez Mag",
"number": "************4242"
},
"guid": "********9f8f573",
"muid": "1c53d81",
"sid": "8853344",
"payment_user_agent": "stripe.js/d67f6c85; stripe-js-v3/d67f6c85",
"time_on_page": "456225",
"referrer": "http://localhost:4200/sign-up",
"key": "pk_test_C2Q1L0"
}

and here is my code:

this.stripeService
.createToken(this.cardNumber, { name: fullname })
.subscribe(result => {
if (result.token) {
//success
}
});

before that I have created three elements and they are showing correctly on the UI:

    this.stripeService.elements(this.elementsOptions)
    .subscribe(elements => {
        this.elements = elements;
        // Only mount the element the first time
        if (!this.cardNumber) {
            this.cardNumber = this.elements.create('cardNumber', {
                style: elementStyles
        });
       this.cardNumber.mount('#card-number');
    }
  });

    this.stripeService.elements(this.elementsOptions)
    .subscribe(elements => {
        this.elements = elements;
        // Only mount the element the first time
        if (!this.cardExpiry) {
            this.cardExpiry = this.elements.create('cardExpiry', {
                style: elementStyles
        });
        this.cardExpiry.mount('#card-expiry');
    }
    });

    this.stripeService.elements(this.elementsOptions)
    .subscribe(elements => {
        this.elements = elements;
        // Only mount the element the first time
        if (!this.cardCvc) {
            this.cardCvc = this.elements.create('cardCvc', {
                style: elementStyles
        });
    this.cardCvc.mount('#card-cvc');
    }
});

[a-antoine]

It works by instanciating only one Elements, and using it create the cardNumber, cardExpiry and cardCvc element fields.