Cómo usar enlaces UTM directos al checkout

/**  
 * IMPORTANT: This pixel can only fire on sessions where the  
 * customer has a cart object, otherwise it will be skipped.  
 * For example, clicking "Buy Now" on a product page skips the cart,  
 * going directly to checkout.  
**/  
function processData({event, cartToken}) {  
  // TODO: Edit MYSHOPIFY_DOMAIN to your domain. E.g.  
  // const MYSHOPIFY_DOMAIN = 'example-store.myshopify.com';  
  const MYSHOPIFY_DOMAIN = '';  
  
  const enableDebug = false;  
  
  // DO NOT EDIT PAST HERE  
  const SESSION_STORAGE_KEY = 'as-customer-trigger-data';  
  const HOST = 'https://start.aftersell.app';  
  
  if (!MYSHOPIFY_DOMAIN) {  
    if (enableDebug) {  
      console.log("UTM pixel didn't fire because of missing Shopify domain");  
    }  
    return;  
  }  
  if (!cartToken) {  
    if (enableDebug) {  
      console.log("UTM pixel didn't fire because of missing cart token");  
    }  
  }  
    
  let existingCustomerData = null;  
  try {  
      existingCustomerData = JSON.parse(  
          sessionStorage.getItem(SESSION_STORAGE_KEY) || 'null'  
      );  
  } catch (ignore) {  
    if (enableDebug) {  
      console.log("UTM pixel didn't fire because malformed user data json");  
    }  
  }  
    
  const allowedUrlParams = [  
        'utm_source',  
        'utm_medium',  
        'utm_campaign',  
        'utm_term',  
        'utm_id',  
        'utm_content',  
    ];  
    
  const searchParams = new URLSearchParams(event.context.window.location.search);  
  let hasCustomerData = false;  
  const customerData = {};  
  for (const param of allowedUrlParams) {  
    const paramValue = searchParams.get(param) || existingCustomerData?.[param];  
    if (paramValue) {  
        hasCustomerData = true;  
        customerData[param] = paramValue;  
    }  
  }  
  
  if (hasCustomerData) {  
    sessionStorage.setItem(SESSION_STORAGE_KEY, JSON.stringify(customerData));  
  
    const postBody = {  
      shop: MYSHOPIFY_DOMAIN,  
      cartToken,  
      checkoutToken: event.data.checkout.token ?? undefined,  
      customerTriggerData: customerData,  
    };  
  
    if (enableDebug) {  
      console.log("UTM pixel fired with the following data:", postBody);  
    }  
      
    fetch(`\${HOST}/api/v1/storefrontSessions`, {  
        method: 'POST',  
        headers: {  
            'Content-Type': 'application/json',  
        },  
        body: JSON.stringify(postBody),  
    });  
  } else {  
    if (enableDebug) {  
      console.log("UTM pixel didn't fire because there was no data to send");  
    }  
  }  
}  
  
analytics.subscribe('checkout_started', (event) => {  
   // minimum realistic time between adding item to cart and clicking checkout  
    const COOKIE_POLLING_INTERVAL_MS = 500;  
  
    let currentCookieValue = getCookieValue({ cookie: document.cookie, cookieName: 'cart' });  
    processData({event, cartToken: currentCookieValue});  
  
    setInterval(() => {  
        const newCookieValue = getCookieValue({ cookie: document.cookie, cookieName: 'cart' });  
        if (newCookieValue !== currentCookieValue) {  
            currentCookieValue = newCookieValue;  
            processData({event, cartToken: newCookieValue});  
        }  
    }, COOKIE_POLLING_INTERVAL_MS);  
});  
  
function getCookieValue({ cookie, cookieName }) {  
    const cartCookieRegex = new RegExp(`^\${cookieName}=`);  
    const cartCookie = cookie  
        .split(';')  
        .map((val) => val.trim())  
        .find((val) => cartCookieRegex.test(val));  
    if (!cartCookie) return null;  
    const cartCookieValue = cartCookie.replace(`\${cookieName}=`, '');  
    return cartCookieValue;  
}