Blog type of "testimonials" -> has articles with a metafield that links to a product ID. Builds a Map of products that have an articles array, with a list of articles that have that metafield relationship. Does 2 requests. One to get a list of the blog posts, then a batch request for products (using the "(id:<number>) OR (id:<number>)") request …

shopify_products_articles.js

const authenticationHeaders = new Headers();
    authenticationHeaders.append("Content-Type", "application/json");
    authenticationHeaders.append("X-Shopify-Storefront-Access-Token", <access-token-here>);

    const articleGraphql = JSON.stringify({
        query: "query {\n    blog(handle: \"testimonials\"){\n        articles(first: 100){\n            edges{\n                node{\n                    id\n                    title\n                    url\n                    metafield(namespace: \"testimonial\", key: \"product\"){\n                        value                        }\n                }\n            }\n        }\n    }\n}",
        variables: {}
    });

    const articleRequest = {
        method: 'POST',
        headers: authenticationHeaders,
        body: articleGraphql,
        redirect: 'follow'
    };

    const cleanGID = (gid) => {
        return gid.split('/').pop();
    }

    const handleArticles = (result) => new Promise((resolve) => {
        const product_id_list = [];
        const edges = JSON.parse(result).data?.blog?.articles?.edges;
        edges.map(node => {
            node = node?.node;
            const gid = node?.metafield?.value;
            const id = cleanGID(gid);
            product_id_list.push(`(id:${id})`);
        })

        resolve([[...new Set(product_id_list)], edges]);
    })

    const gidDecode = (str, clean = false) => {
        const gid = str.includes('gid://') ? str : base64Decode(str);

        if (!clean) {
            return gid;
        }
        return cleanGID(gid);
    }

    const base64Decode = (str) => {
        return decodeURIComponent(atob(str));
    }

    const mappedArticles = (articleNodeArray) => {
        const map = new Map();
        articleNodeArray.map(item => {
            const productID = cleanGID(item.node.metafield.value);
            if (map.has(productID)) {
                map.set(productID, map.get(productID).push(item.node));
            } else {
                map.set(productID, [item.node].flat());
            }
        })
        return map;
    };

    const buildProductList = (products, articleMap) => {
        const productMap = new Map();
        JSON.parse(products).data?.products?.edges.map(item => {
            const productData = item.node;
            const productGid = gidDecode(item.node.id, true)
            productData.articles = articleMap.get(productGid);
            productMap.set(gidDecode(item.node.id, true), productData);
        })
        return productMap;
    }

    const handleProductIDList = (product_id_list, articles) => {
        const query = product_id_list.join(' OR ');
        const cleanedArticles = mappedArticles(articles);

        const productGraphQL = JSON.stringify({
            query: `query {\n  products(query: "${query}", first: 100) {\n    edges {\n      node {\n        id\n        handle\n        featuredImage {\n          url\n        }\n        metafield(namespace: \"my_fields\", key: \"dimensions\") {\n          value\n        }\n      }\n    }\n  }\n}`,
        });

        const productRequest = {
            method: 'POST',
            headers: authenticationHeaders,
            body: productGraphQL,
            redirect: 'follow'
        };

        fetch("https://<shopify-shop-url>.myshopify.com/api/graphql", productRequest)
            .then(response => response.text())
            .then(result => {
                const productMap = buildProductList(result, cleanedArticles);
                console.log('map', productMap);
            })
            .catch(error => console.log('error', error));
    }

    fetch("https://<shopify-shop-url>.myshopify.com/api/graphql", articleRequest)
        .then(response => response.text())
        .then(result => handleArticles(result).then(([product_ids, articles] = data) => handleProductIDList(product_ids, articles)))
        .catch(error => console.log('error', error));