An example of a code effect added to the Update action of a Shopify Customer model that overrides the metafield data in Gadget first, then sends the information to Shopify so that the data stays in sync

shopifyCustomerOnUpdate.js

/**
 * Fetch the ids for metafields on a resource
 */
const fetchMetafieldIds = async ({ resource, shopifyApi, metafieldSchema, id }) => {
  const gidResource = resource.charAt(0).toUpperCase() + resource.slice(1);
  const gid = `gid://shopify/${gidResource}/${id}`;
  return (
    await shopifyApi.graphql(
      `
      query MetafieldIds($id: ID!) {
        metafields: ${resource}(id: $id) {
          ${metafieldSchema.metafields.map(
            ({ namespace, key }) =>
              `${namespace}_${key}: metafield(namespace: ${JSON.stringify(namespace)}, key: ${JSON.stringify(key)}) { id }`
          )}
        }
      }
      `,
      {
        id: gid,
      }
    )
  ).metafields;
};

/**
 * Get the shopify metafield configuration for all metadata fields in `model`
 */
const getModelMetafieldSchema = (model) => {
  const metafields = [];
  const privateMetafields = [];
  for (const field of Object.values(model.fields)) {
    const contributorConfig = field.contributorConfiguration["shopify/contributor/field/metafield"];
    if (!contributorConfig) continue;

    const metafield = contributorConfig.metafield;
    if (!metafield.namespace || !metafield.key) continue;

    if (!metafield.isPrivate) {
      metafields.push({ ...metafield, apiIdentifier: field.apiIdentifier });
    } else {
      privateMetafields.push({ ...metafield, apiIdentifier: field.apiIdentifier });
    }
  }

  return { metafields, privateMetafields };
};

const buildRESTMetafieldsPayload = async ({ resource, shopifyApi, model, record }) => {
  const metafieldSchema = getModelMetafieldSchema(model);
  const metafieldIds = await fetchMetafieldIds({ resource, shopifyApi, metafieldSchema, id: record.id });

  // Make sure the field we're updating has a metafield and that if it has a Shopify id then include id
  return metafieldSchema.metafields.map(({ namespace, key, type, apiIdentifier }) => {
    const gid = metafieldIds[`${namespace}_${key}`]?.id;
    const id = gid ? gid.match(/^gid:\/\/shopify\/[A-Za-z]+\/(\d+)$/)[1] : null;
    return {
      id,
      namespace,
      key,
      type,
      value: record[apiIdentifier],
    };
  });
};

// Once a record has been updated in Gadget, fire off an update to the Shopify API
// to keep our meta fields in sync
module.exports = async ({ model, record, connections }) => {
  const shopifyApi = await connections.shopify.forShopDomain("mycoolshop.myshopify.com");

  // If customer's order count is greater than 10, mark them with a VIP metafield flag
  if (record.ordersCount > 10) {
    // Set VIP flag to true
    // This field will have been set up as a metafield in the Shopify Customer model
    record.isVip = true;

    // Update metafield on a resource through the REST API
    await shopifyApi.customer.update(Number(record.id), {
      metafields: await buildRESTMetafieldsPayload({
        resource: "customer",
        shopifyApi,
        model,
        record,
      }),
    });
  }
};