Ts-node module resolution is not respected

[lantos1618]

Search Terms

ts-node module type resolution package.json
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /...

Expected Behavior

when "moduleType" is specified in ts-config.json it should ignore the "type": "module" specified in package.json

tsconfig.json

  "ts-node": {
    "moduleTypes": {
      "*": "commonjs"
    }
  },

package.json

{
  "name": "typescript-incorrect-behaviour",
  "version": "1.0.0",
  "description": "",
  "type": "module",
  "main": "index.js",

Actual Behavior

"type": "module", is respected when tsconfig.json should be respected.

Even passing "NODE_OPTIONS='--import-type=commonjs'" does not get respected.

throws

Debugger attached.
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for ~/Desktop/typescript-incorrect-behaviour/src/index.ts
    at new NodeError (node:internal/errors:372:5)
    at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:76:11)
    at defaultGetFormat (node:internal/modules/esm/get_format:118:38)
    at defaultLoad (node:internal/modules/esm/load:21:20)
    at ESMLoader.load (node:internal/modules/esm/loader:407:26)
    at ESMLoader.moduleProvider (node:internal/modules/esm/loader:326:22)
    at new ModuleJob (node:internal/modules/esm/module_job:66:26)
    at ESMLoader.#createModuleJob (node:internal/modules/esm/loader:345:17)
    at ESMLoader.getModuleJob (node:internal/modules/esm/loader:304:34)
    at processTicksAndRejections (node:internal/process/task_queues:96:5) {
  code: 'ERR_UNKNOWN_FILE_EXTENSION'
}

Steps to reproduce the problem

npm init
npm install typescript ts-node @types/node
tsc --init
create a src/index.ts with console.log("hello") inside
add "type": "module" to package.json
add "start": "ts-node src/index.ts" to package.json
npm start

Minimal reproduction

I have an example here.
https://github.com/lantos-lgtm/typescript-incorrect-behaviour

git clone  https://github.com/lantos-lgtm/typescript-incorrect-behaviour
cd typescript-incorrect-behaviour
npm install
npm start

Specifications

ts-node v10.9.1
node v16.16.0
compiler v4.7.4

• tsconfig.json, if you're using one:

{
  "ts-node": {
    "moduleTypes": {
      "*": "commonjs"
    }
  },
  "compilerOptions": {
    "target": "es2016",
    "module": "commonjs",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "skipLibCheck": true
  }
}

• package.json:

{
  "name": "typescript-incorrect-behaviour",
  "version": "1.0.0",
  "description": "",
  "type": "module",
  "main": "index.js",
  "scripts": {
    "start": "ts-node src/index.ts",
    "start_node_env_override": "ts-node NODE_OPTIONS='--import-type=commonjs' src/index.ts",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@types/node": "*",
    "ts-node": "^10.9.1",
    "typescript": "^4.7.4"
  }
}

• Operating system and version: macos 12.5
• If Windows, are you using WSL or WSL2?: none

[cspotcode]

I double-checked the docs, looks like moduleTypes might be configured incorrectly:
https://typestrong.org/ts-node/docs/module-type-overrides

[lantos1618]

Just updated to cjs still same response

[lantos1618]

Or by

  "ts-node": {
    "moduleTypes": {
      "src/**/*.ts": "cjs"
    },
    "esm": true,
 }

[cspotcode]

I think you had two problems: First, the "commonjs" should have been "cjs". Second, the glob pattern "*" was wrong.

[callmeberzerker]

I am bumping my head against the same issue. Did you found a more idiomatic solution @lantos-lgtm ? I really don't wanna do the index.cjs file approach as above, but whatever I do I can't make moduleTypes to be respected as cjs.

[lantos1618]

idiomatic, no.
hacky, yes.

I have two tsconfigs now and then specify which config to use using package.json

    "server": "nodemon --project=tsconfig.server.json src/server/server.ts",
    "frontend": "nodemon --project=tsconfig.frontend.json src/index.ts"

I'm probably wrong but "nothing about ts is idiomatic." (joke). I saw you are doing a startup, I am doing the same. I am kinda deep into it change but looking back I personally would not choose TS for mid/long term development before you really consider what is important to you. My cofounder and I spent way to long on things like this when we should have been actually writing our business logic...

[callmeberzerker]

No worries I never ever wanna go back to the era before TypeScript -> these quirks and ecosystem issues included. Yeah TS/JS has a wonky ecosystem. And ESM specifically is such a wonky thing in NodeJS even if you exclude TS.

P.S. In the end I managed to get it working idiomatically. Here is my tsconfig.json configuration for the ts-node property:

{      
        "compilerOptions": {
		// stuff here
	},,
	"ts-node": {
		"moduleTypes": {
			"**/*.ts": "cjs"
		},
		"transpileOnly": true,
		"preferTsExts": true,
		"esm": false,
		"require": ["tsconfig-paths/register"],
		"compilerOptions": {
			"preserveValueImports": false
		}
	}
}