Troubleshooting Empty Shipping Options in ESHOPMAN Development Mode

Understanding Empty Shipping Options in ESHOPMAN Development

As an ESHOPMAN developer, you might occasionally encounter perplexing issues during the development of your headless storefronts, especially when integrating with HubSpot CMS. One such scenario involves the ESHOPMAN Store API's /store/shipping-options route unexpectedly returning empty results in development mode, even when all your shipping configurations are correctly set up and data is present.

This insight delves into a community discussion surrounding this exact problem, offering valuable debugging steps and a common root cause that ESHOPMAN developers should be aware of when building on Node.js/TypeScript.

The Problem: Empty Shipping Options in Dev Mode

A community member reported an issue where the built-in GET /store/shipping-options route, crucial for displaying available shipping methods on a HubSpot CMS-powered storefront, returned {"shipping_options":[]} when running their ESHOPMAN instance in development mode (eshopman develop). This occurred despite having a fully configured store with a cart, fulfillment set, service zone, geo zone, and at least one shipping option.

The expected behavior was for the API to return the matching shipping options, allowing the storefront to present choices to the customer. The discrepancy was particularly puzzling because direct calls to the underlying workflow and even the route handler function itself, when invoked outside the standard Express routing chain, produced the correct results.

Debugging and Investigation

The developer undertook a thorough investigation, which is a great example of ESHOPMAN best practices for debugging:

• Verifying Core Logic: They confirmed that the built-in route handler's code was correct by calling the same function directly with the same request object. This helped isolate the issue to the routing or middleware layer rather than the core business logic.
• Observing Middleware Behavior: A key observation was that validateAndTransformQuery was registered twice in the Express stack for this specific route, suggesting a potential conflict or misconfiguration in the route's middleware chain.
• Implementing a Custom Route Override: To further test and provide a workaround, the developer created a custom route override at src/api/store/shipping-options/route.ts. This is a powerful feature in ESHOPMAN, allowing developers to extend or modify core API behavior. The custom route, with identical logic to the core handler, worked perfectly:

import { EshopmanRequest, EshopmanResponse } from "@eshopmanjs/framework/http";
import { listShippingOptionsForCartWorkflow } from "@eshopmanjs/eshopman/core-flows";

export async function GET(req: EshopmanRequest, res: EshopmanResponse) {
  const cart_id = req.filterableFields?.cart_id || req.query.cart_id;
  const is_return = req.filterableFields?.is_return;

  const workflow = listShippingOptionsForCartWorkflow(req.scope);
  const { result: shipping_options } = await workflow.run({
    input: { cart_id, is_return: !!is_return },
  });

  res.json({ shipping_options });
}

The Resolution: Identifying a Custom Module Override

After extensive debugging, the developer discovered the root cause: a custom ESHOPMAN module or integration was inadvertently overriding the shipping option logic. In this specific case, a third-party project was interfering with the standard ESHOPMAN shipping option processing.

This highlights a critical point for ESHOPMAN developers: while the platform's modularity and extensibility are powerful, custom modules or integrations can sometimes introduce unexpected behavior by overriding core functionalities. When facing issues with built-in ESHOPMAN Store API routes, especially those that appear to be correctly configured but yield incorrect results, always consider the possibility of an override by a custom plugin or integration.

Key Takeaway for ESHOPMAN Developers

If your ESHOPMAN Store API endpoints, particularly /store/shipping-options, return empty or incorrect data in development mode, and you've confirmed your core data setup is correct, investigate your custom ESHOPMAN modules, plugins, or third-party integrations. These custom additions, while enhancing your HubSpot-integrated headless commerce experience, can sometimes inadvertently alter or replace core ESHOPMAN functionalities, leading to unexpected outcomes. Debugging by creating a temporary custom route override, as demonstrated, can be an effective way to isolate whether the issue lies within the core platform or a custom extension.