Stripe API update

Stripe has updated its API because the old ones do not respect a European regulation. How do I update the code on the site, I have now integrated the old API like this:

PAGE:

import wixUsers from 'wix-users';
import wixLocation from 'wix-location';
import wixWindow from 'wix-window';
import {createToken, encodeCard} from "public/stripeAPI.js";
import {charge} from 'backend/stripePrivate';

$w.onReady(function () {
 // TODO: write your page related code here...

});

function createCard() {
 return {
 "name": $w("#iptName").value,
 "number": $w("#iptCardNumber").value,
 "cvc": $w("#iptCVC").value,
 "exp_year": $w("#iptYear").value,
 "exp_month": $w("#iptMonth").value
    };
}


export function payNow() {
 /*var euro = 1;

    if ($w('#checkbox1').checked){
         euro = euro + 5;
    }
    */

    console.log($w('#dbMembers').getCurrentItem())
    console.log()


 let payment = {
 "amount": ($w('#checkbox2').value * 100),
 "currency": "EUR",
 "description": "trial"
    }
    createToken(encodeCard(createCard()))
        .then((token) => {
            charge(token, payment, wixUsers.currentUser.id)
                .then((response) => {
 if(response.chargeId) {
 //payment success
                        $w('#response').text = response.chargeId;
                        $w('#lblResponse').text = "Pagato!!!";
                    }
 else {
 //payment fail
                        $w('#response').text = response.error;
                        $w('#lblResponse').text = "Processing error (from Stripe):";                        
                    }
                    $w('#response').show();
                });
        });
}




export function button1_click(event) {
    payNow()
}

PUBLIC:

import {fetch} from 'wix-fetch';

////////////////////////////////////////////////
// A "test key" is used for this example.
// Use a "live key" for a production site.
// Go to stripe.com to get your own key.
// https://stripe.com/docs/keys  
const apiKey = "pk_test_"; // (public key)
// The publishable key is just used to identify your account.
// It does not provide permission to perform any function
// except for creating a token, and can therefore be used
// in a public file.
////////////////////////////////////////////////

// This function uses the Stripe API to get a card token.
// A card token is a secure representation of the card
// and can only be used once.
// https://stripe.com/docs/api#create_card_token
export async function createToken(card) {

 const response = await fetch("https://api.stripe.com/v1/tokens", {
        method: 'post',
        headers: {
 "Content-Type": "application/x-www-form-urlencoded",
 "Authorization": "Bearer " + apiKey
        },
        body: card
    });
 if (response.status >= 200 && response.status < 300) {
 const json = await response.json()
 return json.id;
    }
 const responseText = await response.text();
 return response.status;
}

// Builds the fetch body from the array of card details.
export function encodeCard(card) {
 let encoded = "";
 for (let [k, v] of Object.entries(card)) {
        encoded = encoded.concat("card[", k, "]=", encodeURI(v), "&");
    }
 return encoded.substr(0, encoded.length - 1);
}

BACKEND:

import {fetch} from 'wix-fetch';

////////////////////////////////////////////////
// A "test key" is used for this example.
// Use a "live key" for a production site.
// Go to stripe.com to get your own key.
// https://stripe.com/docs/keys
const apiKey = "sk_test_"; // (secret key)
// The key in use in this file is the private API key.
// The private key is used to perform all actions and
// should be kept confidential and guarded and
// therefore is only to be used in backend files.
////////////////////////////////////////////////

export async function charge(token, payment, userId) {

 const cart = payment;
 const response = await fetch("https://api.stripe.com/v1/charges", {
        method: 'post',
        headers: {
 "Content-Type": "application/x-www-form-urlencoded",
 "Authorization": "Bearer " + apiKey 
        },
        body: encodeBody(token, cart)
    });
 if (response.status >= 200 && response.status < 300) {
 // transaction successful - get charge ID
 const ret = await response.json();
 
 return {"chargeId": ret.id};
    }
 // transaction failed - return error type
 let res = await response.json();
 let err = res.error.type;
 return {"error": err};
}

function encodeBody(token, cart) {
 let encoded = "";
 for (let [k, v] of Object.entries(cart)) {
        encoded = encoded.concat(k, "=", encodeURI(v), "&");
    }
    encoded = encoded.concat("source=", encodeURI(token));
 return encoded;
}

But the tripe guidelines say to change like this but I don't know how: https://stripe.com/docs/payments/payment-intents/migration Can anyone show me how to update the code?