esm vs. commonjs

[alex-dixon]

Hello! Thank you for this library.

I am receiving the following typescript error on 0.12.1:

TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("effect-http")' call instead.   To convert this file to an ECMAScript module, change its file extension to '.mts', or add the field "type": "module" to 'package.json'.

I was not seeing this error in past versions.

Is the library no longer commonjs compatible?

[sukovanej]

Hey, I'm aiming to support both cjs and esm. Unfortunately, I was unable to reproduce the typescript error but I checked there is indeed a problem with the cjs version. Please try with version 0.14.1 and let me know.

[alex-dixon]

Thank you. Just checked on 0.14.1 and I'm seeing the same thing.

On a local fork if I remove "type": "module" from the effect-http package.json it appears to fix it. Not sure what other havoc that change would make. For whatever it's worth it looks like other effect packages do not set "type": "module".

[sukovanej]

Alright, I tried that - v0.14.3. Do you have the repo it's not working on available publically, or share a tsconfig.js? I'm trying it on my sample cjs and I don't see the error so it might be a specific configuration in the tsconfig.

[alex-dixon]

Yes. Apologies. Meant to do that initially. Here it is:

{
  "compilerOptions": {
    "target": "es2022",
    "module": "commonjs",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "moduleResolution": "Node16",
    "exactOptionalPropertyTypes": true,
    "outDir": "./dist",
    "skipLibCheck": true,
    "plugins": [
      {
        "name": "@effect/language-service"
      }
    ]
  }
}

[alex-dixon]

Confirmed working on my end on 0.14.3

[sukovanej]

Aha! It is an "incorrect" conditional export setting in effect-http for the node16 resolution setting. For whatever reason, typescript demands *.d.cts declaration files for require imports (microsoft/TypeScript#50466) and ignores the specified *.d.ts. The DX of making typescript work is really something... 😢

Anyway, thanks a lot for sharing the issue. I'll discuss the proper package configuration with people on the effect discord. For now, the setup should work for both esm and cjs.