ESM build is broken, cannot import `@hashgraph/stablecoin-npm-sdk` in Node.js ESM

[kierzniak]

I would like to use stablecoin studio sdk in my plugin but because of problems with ESM imports I have errors. @hashgraph/stablecoin-npm-sdk@4.2.0 cannot be imported in any Node.js ESM project ("type": "module"). The ESM build output (build/esm/) has three categories of bugs that prevent it from loading.

Environment

• @hashgraph/stablecoin-npm-sdk: 4.2.0
• Node.js: v24.14.1 (also reproducible on v20+)

Minimal reproduction

mkdir repro && cd repro
echo '{ "type": "module", "dependencies": { "@hashgraph/stablecoin-npm-sdk": "^4.2.0" } }' > package.json
npm install
node -e "import('@hashgraph/stablecoin-npm-sdk').then(m => console.log(Object.keys(m)))"

Issue 1: Missing .js extensions in relative imports (162 occurrences)

Node.js ESM requires file extensions in relative import specifiers (Node.js docs).

Entry point — build/esm/src/index.js:23:

// ❌ Actual (missing .js extension)
export * from './port/in/index';

// ✅ Expected
export * from './port/in/index.js';

Error:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '.../build/esm/src/port/in/index'
imported from .../build/esm/src/index.js

Issue 2: require() used inside ESM file

File: build/esm/src/port/out/hs/walletconnect/HederaWalletConnectTransactionAdapter.js:52

// ❌ require() is not available in ESM scope
const { SupportedWallets } = require('@hashgraph/stablecoin-npm-sdk');

Error:

ReferenceError: require is not defined in ES module scope, you can use import instead

This is also a circular self-import (the SDK requiring itself). It should use a regular ESM import:

// ✅ Expected
import { SupportedWallets } from '@hashgraph/stablecoin-npm-sdk';

Same file also has dynamic require() calls at lines 56-58:

const hwc = require('@hashgraph/hedera-wallet-connect');
const appkit = require('@reown/appkit');

These should use dynamic import() instead.

Issue 3: Directory import through package exports wildcard

File: build/esm/src/app/service/TransactionService.js:42

// ❌ Directory import — not supported through exports field
import * as Factories from '@hashgraph/stablecoin-npm-contracts/typechain-types/factories/contracts';

@hashgraph/stablecoin-npm-contracts/package.json exports map:

{
  "exports": {
    "./typechain-types/*": {
      "import": "./build/typechain-types/*",
      "require": "./build/typechain-types/*"
    }
  }
}

Error:

Error [ERR_UNSUPPORTED_DIR_IMPORT]: Directory import '.../factories/contracts' is not supported
resolving ES modules

The wildcard * in exports does not match directory paths. The import should include the explicit file:

// ✅ Expected
import * as Factories from '@hashgraph/stablecoin-npm-contracts/typechain-types/factories/contracts/index.js';

Note: This issue also exists in the CJS build (build/cjs/src/app/service/TransactionService.js:81).

Impact

• Any ESM project ("type": "module" in package.json) cannot use @hashgraph/stablecoin-npm-sdk
• This affects all modern Node.js projects using ESM, Next.js apps, and any bundler that relies on Node.js ESM resolution
• The CJS build (build/cjs/) works correctly (except for Issue 3)

Additional: @hashgraph/stablecoin-npm-contracts has simillar issues.