How can we retrieve the ID of a user created Cart within a Theme App Extension?

For more background, I want to update a Cart Attribute within my Theme App Extension with a GraphQL Mutation. This Mutation accepts the Cart ID as a param but I’m not sure how to get the cart ID of current user.

Hello @triplesingle

You can get the Current user Cart ID in the theme extension by shopify cookies for that use the code below.

// 1. function for getting cookies value
const getCookie = cname => {
  var name = cname + "=";
  var ca = document.cookie.split(';');
  for (var i = 0; i < ca.length; i++) {
    var c = ca[i];
    while (c.charAt(0) == ' ') {
      c = c.substring(1);
    }
    if (c.indexOf(name) == 0) {
      return c.substring(name.length, c.length);
    }
  }
  return "";
};
// 2. Get the current user cart ID 
const cartID=getCookie("cart")?`gid://shopify/Cart/${getCookie("cart")}`:""

You get cartId = gid://shopify/Cart/Z2NwLXVzLWVhc3QxOjAxSFhSODRYMERHNVo3WlRQMVI1UUZLMU45 (for example )

use this ID in your graphQl Mutition or query

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