ESM mode with ts-node breaks TypeScript path alias resolution in cucumber-js

[samydoesit]

👓 What did you see?

When using cucumber-js with ts-node as the loader in ESM mode, TypeScript path aliases specified in tsconfig.json fail to resolve.

Path aliases are not resolved, resulting in module resolution errors when attempting to execute tests.

Error:

Error: Cannot find package '@/index.js' imported from /cucumber-typescript-path-alias-reproduction/features/step_definitions/steps.ts
    at packageResolve (/cucumber-typescript-path-alias-reproduction/node_modules/ts-node/dist-raw/node-internal-modules-esm-resolve.js:757:9)
    at moduleResolve (/cucumber-typescript-path-alias-reproduction/node_modules/ts-node/dist-raw/node-internal-modules-esm-resolve.js:798:18)
    at Object.defaultResolve (/cucumber-typescript-path-alias-reproduction/node_modules/ts-node/dist-raw/node-internal-modules-esm-resolve.js:912:11)
    at /cucumber-typescript-path-alias-reproduction/node_modules/ts-node/src/esm.ts:218:35
    at entrypointFallback (/cucumber-typescript-path-alias-reproduction/node_modules/ts-node/src/esm.ts:168:34)
    at /cucumber-typescript-path-alias-reproduction/node_modules/ts-node/src/esm.ts:217:14
    at addShortCircuitFlag (/cucumber-typescript-path-alias-reproduction/node_modules/ts-node/src/esm.ts:409:21)
    at resolve (/cucumber-typescript-path-alias-reproduction/node_modules/ts-node/src/esm.ts:197:12)
    at nextResolve (node:internal/modules/esm/hooks:865:28)
    at Hooks.resolve (node:internal/modules/esm/hooks:303:30)

✅ What did you expect to see?

TypeScript path aliases should resolve correctly when cucumber-js is run in ESM mode using ts-node.

📦 Which tool/library version are you using?

• Cucumber-js version: 10.6.0
• ts-node version: 10.9.2
• TypeScript version: 5.4.5
• Node.js version: 20.11.1

🔬 How could we reproduce it?

Steps to Reproduce

1. Clone the provided repository from https://github.com/samydoesit/cucumber-typescript-path-alias-reproduction
2. Install dependencies using npm install
3. Attempt to run the tests using npm test
4. Notice the module resolution errors related to TypeScript path aliases

📚 Any additional context?

No response

[GRmeB]

+1 Same issue here...

[davidjgoss]

Thanks @samydoesit for raising, and taking the time to make that repro.

I've looked at the config there, but my understanding is that it would not work with or without Cucumber. From the relevant ts-node documentation:

..."paths" are intended to describe mappings that the build tool or runtime already performs, not to tell the build tool or runtime how to resolve modules. In other words, they intend us to write our imports in a way node already understands. For this reason, ts-node does not modify node's module resolution behavior to implement "paths" mappings.

ts-config-paths tends to be used for this, but from what I can see lacks ESM support for now, so unfortunately to have path mapping like this you may need to go back to CommonJS output.

[samydoesit]

Thanks for your quick response. :) I thought maybe there is another way.

We will keep the CommonJS output for now.