Why can't I access Cart ID with Storefront API via GraphQL?

[mikesynan]

Hi, I'm having trouble accessing cart ID with Storefront API. This is with a custom private app I need to develop for a client.

const express = require('express');
const cors = require('cors');
const axios = require('axios');
require('dotenv').config();

const app = express();

app.use(cors());
app.use(express.json());

app.post('/checkout-update', async (req, res) => {
  try {
    const checkout = req.body;
    
    console.log('THIS IS THE CHECKOUT ID:', checkout.id); 
    const encodedCheckoutId = Buffer.from(`gid://shopify/Checkout/${checkout.id}`).toString('base64');
    console.log('Encoded Checkout ID:', encodedCheckoutId);

    const graphqlEndpoint = `https://${process.env.SHOP_NAME}.myshopify.com/api/2023-07/graphql.json`;
    const headers = {
      'X-Shopify-Storefront-Access-Token': process.env.STOREFRONT_ACCESS_TOKEN,
      'Content-Type': 'application/json'
    };

    const checkoutQuery = `
      query getCheckout($checkoutId: ID!) {
        node(id: $checkoutId) {
          ... on Checkout {
            id
            webUrl
            lineItems(first: 5) {
              edges {
                node {
                  title
                  quantity
                }
              }
            }
          }
        }
      }
    `;

    const variables = {
      checkoutId: encodedCheckoutId
    };

    const response = await axios.post(graphqlEndpoint, { query: checkoutQuery, variables }, { headers });

    if (response.data && response.data.data) {
      console.log('GraphQL Response:', JSON.stringify(response.data.data, null, 2));
    } else {
      console.log('Unexpected GraphQL response:', JSON.stringify(response.data, null, 2));
    }
  } catch (error) {
    console.error('Internal Server Error:', error);
  }

  res.status(200).send('GraphQL Test Completed');
});

const port = process.env.PORT || 3001;
app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});

Give me this response:

0|index  | Server running on port 3003
0|index  | THIS IS THE CHECKOUT ID: 981820079255243500
0|index  | This is the encoded id: Z2lkOi8vc2hvcGlmeS9DaGVja291dC85ODE4MjAwNzkyNTUyNDM1MDA=
0|index  | Encoded Checkout ID: Z2lkOi8vc2hvcGlmeS9DaGVja291dC85ODE4MjAwNzkyNTUyNDM1MDA=
0|index  | GraphQL Response: {
0|index  |   "node": null
0|index  | }

 As you can see I get checkout ID from the webhook but get a null response in my query. Any help would be greatly appreciated.