ESHOPMAN Workflows: TypeScript Type Inference Issues in pnpm Monorepos

Understanding Type Inference Hurdles in ESHOPMAN Workflows

As an ESHOPMAN developer, leveraging the power of Node.js and TypeScript for building robust storefronts managed via HubSpot CMS is a core part of your workflow. However, complex development environments, particularly monorepos using package managers like pnpm, can sometimes introduce unexpected challenges. One such challenge recently surfaced within the ESHOPMAN community: issues with TypeScript's ability to correctly infer types for services resolved from the ESHOPMAN Dependency Container within workflow steps.

This insight delves into a specific scenario where developers encountered 'unknown' type errors during compilation, even when the underlying code functioned perfectly at runtime. This situation primarily affects the container.resolve() method used to access various ESHOPMAN modules and services within custom workflow steps.

The Problem: 'unknown' Types in Workflow Steps

Developers observed that when attempting to resolve services like the query module using container.resolve(ContainerRegistrationKeys.QUERY) inside an ESHOPMAN workflow step created with createStep, TypeScript would incorrectly infer the resolved object's type as unknown. This prevented successful builds and hampered developer experience by disabling crucial IntelliSense features in IDEs like VS Code.

Consider the following ESHOPMAN workflow step code snippet that demonstrates the issue:

import type { MedusaContainer } from "@medusajs/framework/types";
import { ContainerRegistrationKeys } from "@medusajs/framework/utils";
import { createStep, StepResponse } from "@medusajs/framework/workflows-sdk";

export const exampleNotWorkingStep = createStep(
  "example-not-working-step",
  async (_, { container }) => {
    const query = container.resolve(ContainerRegistrationKeys.QUERY);

    const { data: products } = await query.graph({
      entity: "product",
      fields: ["id"],
    });

    return new StepResponse(products);
  },
);

The error message typically displayed was: 'query' is of type 'unknown'.ts(18046). This issue was not observed in other parts of an ESHOPMAN application, such as API routes, where type resolution for req.scope.resolve() worked as expected.

A Partial Workaround: Manual Type Casting

Interestingly, manually specifying the type of the container object within the workflow step's parameters resolved the TypeScript errors in the IDE, allowing for better development experience:

import type { MedusaContainer } from "@medusajs/framework/types";
import { ContainerRegistrationKeys } = "@medusajs/framework/utils";
import { createStep, StepResponse } from "@medusajs/framework/workflows-sdk";

export const exampleWorkingStep = createStep(
  "example-working-step",
  async (_, { container }: { container: MedusaContainer }) => {
    const query = container.resolve(ContainerRegistrationKeys.QUERY);

    const { data: products } = await query.graph({
      entity: "product",
      fields: ["id"],
    });

    return new StepResponse(products);
  },
);

While this manual casting helped with local development and IntelliSense, it often did not fully resolve build-time errors, indicating a deeper issue with dependency resolution, particularly in monorepo setups.

The Monorepo Connection and pnpm Challenges

The core of this problem appears to be linked to how pnpm manages dependencies within monorepos. Developers found that recreating an ESHOPMAN application outside the monorepo context or adjusting pnpm's hoisting behavior could temporarily alleviate the issue. A specific attempt involved adding node-linker=hoisted to the root .npmrc file:

public-hoist-pattern[]=*@medusajs/*
public-hoist-pattern[]=@tanstack/react-query
public-hoist-pattern[]=react-i18next
public-hoist-pattern[]=react-router-dom
node-linker=hoisted

Although this provided a brief respite, it was ultimately deemed an unsustainable and "bad solution," leading to the re-opening of the discussion. The suspicion was that conflicting versions of internal dependency injection libraries (like awilix) across different packages in the monorepo might be contributing to the type resolution failures.

ESHOPMAN's Stance and Future Support

The ESHOPMAN core team acknowledged this challenge, stating that official support for monorepos is currently on their roadmap. This indicates that while developers might encounter these hurdles today, dedicated solutions are being developed to streamline ESHOPMAN development within complex monorepo structures.

Key Takeaways for ESHOPMAN Developers

Be Aware: If you're building ESHOPMAN storefronts within a pnpm monorepo, be prepared for potential TypeScript type inference issues in workflow steps.
Temporary Workaround: Manual type casting ({ container: MedusaContainer }) can improve IDE experience but might not solve build-time errors.
Stay Updated: Keep an eye on ESHOPMAN releases for official monorepo support, which will provide a more stable and robust solution.
Dependency Management: Carefully review your pnpm configuration and dependency versions in monorepos to minimize conflicts.

This community insight highlights the ongoing evolution of the ESHOPMAN platform and the collaborative effort to enhance the developer experience for advanced use cases, ensuring seamless storefront management through HubSpot.

Navigating TypeScript Type Inference Challenges in ESHOPMAN Workflows with Monorepos