TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"

[luyifo]

Search Terms

When the node version is 18.20.0, running TS-node --esm **.ts displays TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts". Runs successfully after the Node version is reduced to 16.20.2.

PS D:\Testspace\ts-node-demo> pn dev

> [email protected] dev D:\Testspace\ts-node-demo
> ts-node-esm src/index.ts

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for D:\Testspace\ts-node-demo\src\index.ts
    at new NodeError (node:internal/errors:405:5)
    at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:136:11)
    at defaultGetFormat (node:internal/modules/esm/get_format:182:36)
    at defaultLoad (node:internal/modules/esm/load:101:20)
    at nextLoad (node:internal/modules/esm/hooks:864:28)
    at load (D:\Testspace\ts-node-demo\node_modules\.pnpm\[email protected]_@[email protected][email protected]\node_modules\ts-node\dist\child\child-loader.js:19:122)
    at nextLoad (node:internal/modules/esm/hooks:864:28)
    at Hooks.load (node:internal/modules/esm/hooks:447:26)
    at MessagePort.handleMessage (node:internal/modules/esm/worker:196:24)
    at [nodejs.internal.kHybridDispatch] (node:internal/event_target:786:20) {
  code: 'ERR_UNKNOWN_FILE_EXTENSION'
}
 ELIFECYCLE  Command failed with exit code 1.
PS D:\Testspace\ts-node-demo> nvm list

  * 18.20.0 (Currently using 64-bit executable)
    16.20.2
PS D:\Testspace\ts-node-demo> nvm use 16.20.2
Now using node v16.20.2 (64-bit)
PS D:\Testspace\ts-node-demo> pn dev

> [email protected] dev D:\Testspace\ts-node-demo
> ts-node-esm src/index.ts

hello world
PS D:\Testspace\ts-node-demo> 

Expected Behavior

Actual Behavior

Steps to reproduce the problem

Minimal reproduction

Specifications

• ts-node version: 10.9.2
• node version: 18.20.0
• TypeScript version: 5.4.5
• tsconfig.json, if you're using one:

{
  "compilerOptions": {
    "rootDir": "./src",
    "target": "es2016", 
    "module": "NodeNext", 
    "moduleResolution": "NodeNext",
    "esModuleInterop": true, 
    "forceConsistentCasingInFileNames": true, 
    "strict": true, 
    "skipLibCheck": true, 
    "verbatimModuleSyntax": true,
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true
  }
}

• package.json:

{
  "type": "module",
  "name": "ts-node-demo",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "dev": "ts-node-esm src/index.ts",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "ts-node": "^10.9.2",
    "typescript": "^5.4.5"
  }
}

• Operating system and version: Windows 11 Pro 10.0.22631 Build 22631
• If Windows, are you using WSL or WSL2?:

[etulikov]

I had the same issue, downgrade Node to 18.18 help. My engines:

"engines": {
    "node": ">=18.18.0 <18.19.0"
  },

[EvilCodeMorty]

Have you solved this problem?I switched the versions of 22,18 and 16 with different problems, and the configuration file has been modified, but it still doesn't work

[EvilCodeMorty]

"module": "CommonJS", "esModuleInterop": true,

[EvilCodeMorty]

My code compilation is no problem, I specially configured a file for "ts-node", code compilation is another file, anyway just to see the state of writing code, so I specially configured a file for "ts-node", compilation is another file;"tsconfig.dev.json"and"tsconfig.json"

[EvilCodeMorty]

"dev": "cross-env TS_NODE_PROJECT=tsconfig.dev.json nodemon --exec ts-node src/main.ts",

[EvilCodeMorty]

"dev": "cross-env TS_NODE_PROJECT=tsconfig.dev.json nodemon --exec ts-node src/main.ts",

[lhapaipai]

seems to work for me with node and --loader flag

{
  "scripts": {
-    "not-work": "ts-node-esm src/main.ts",
+    "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts"
  }
}

node: v20.5.0 ts-node: v10.9.2

[kyledetella]

seems to work for me with node and --loader flag

{
  "scripts": {
-    "not-work": "ts-node-esm src/main.ts",
+    "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts"
  }
}

node: v20.5.0 ts-node: v10.9.2

This worked for me. Thanks @lhapaipai

[meotimdihia]

try to use tsx instead. It works flawlessly for me.

[ranamaniz]

seems to work for me with node and --loader flag

{
  "scripts": {
-    "not-work": "ts-node-esm src/main.ts",
+    "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts"
  }
}

node: v20.5.0 ts-node: v10.9.2

worked for me too thanks

[douglascayers]

seems to work for me with node and --loader flag

{
  "scripts": {
-    "not-work": "ts-node-esm src/main.ts",
+    "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts"
  }
}

node: v20.5.0 ts-node: v10.9.2

Thanks @lhapaipai!

In my scenario, I had to also workaround the following error. I think it stems from my project does not have a top-level tsconfig.json, but rather sub-folders define different configs similar to a monorepo. So I either had to manually cd down into a sub-folder then run the command, or I could have node figure it out via the import command.

Object.defineProperty(exports, "__esModule", { value: true });
                      ^
ReferenceError: exports is not defined in ES module scope

My modified command is:

{
  "scripts": {
-   "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts"
+   "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning -e \"import('${0}');\""
  }
}

Example Usage:

yarn dev path/to/my/file.ts

[lhymmEU]

seems to work for me with node and --loader flag

{
  "scripts": {
-    "not-work": "ts-node-esm src/main.ts",
+    "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts"
  }
}

node: v20.5.0 ts-node: v10.9.2

Thanks @lhapaipai!

In my scenario, I had to also workaround the following error. I think it stems from my project does not have a top-level tsconfig.json, but rather sub-folders define different configs similar to a monorepo. So I either had to manually cd down into a sub-folder then run the command, or I could have node figure it out via the import command.

Object.defineProperty(exports, "__esModule", { value: true });
                      ^
ReferenceError: exports is not defined in ES module scope

My modified command is:

{
  "scripts": {
-   "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts"
+   "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning -e \"import('${0}');\""
  }
}

Example Usage:

yarn dev path/to/my/file.ts

Awesome, that solved my problem. Thanks!

According to the warnings, I've also added a workaround for the "experimentalWarning" issue. I created a "loader.js" in my project root's folder:

import { register } from "node:module";
import { pathToFileURL } from "node:url";

// Register the TypeScript loader
register("ts-node/esm", pathToFileURL('./'));

Then I changed my package.json to:

{
  "scripts": {
      "dev": "node --import './loader.js' src/index.ts"
  }
}

[AmosTmg]

It runs when I change the type to commonjs in package.json.

[natesilva]

It runs when I change the type to commonjs in package.json.

This breaks things if you are using NPM modules that require ESM.

[atjain02]

seems to work for me with node and --loader flag

{ "scripts": {

• "not-work": "ts-node-esm src/main.ts",

• "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts" } } node: v20.5.0 ts-node: v10.9.2

Is this still the best solution? Seems that suppressing these warnings must be a temp solution not fit for production?

[zurmokeeper]

seems to work for me with node and --loader flag

{ "scripts": {

• "not-work": "ts-node-esm src/main.ts",

• "dev": "node --loader ts-node/esm --no-warnings=ExperimentalWarning src/main.ts" } } node: v20.5.0 ts-node: v10.9.2

node: v20.18.1 ts-node: v10.9.2

It's still not working.

node:internal/modules/run_main:128
    triggerUncaughtException(
    ^
[Object: null prototype] {
  [Symbol(nodejs.util.inspect.custom)]: [Function: [nodejs.util.inspect.custom]]
}

Node.js v20.18.1

[mxshdev]

Works for me:

node --swc main.ts

[timjam]

Last week ts-node was working without any issues. Now it's giving me headache. Is there an issue with the latest ts-node and typescript or some incompatibility issue with node and ts-node or what is causing this?

Currently the issue can be reproduced by following these steps:

1. Initialise a new completely empty project a. mkdir test b. pnpm init
2. pnpm add -D ts-node typescript
3. touch main.ts
4. echo "console.log('Hello world')" > main.ts
5. pnpm exec ts-node main.ts

This will now first throw you an error

(node:62836) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node --trace-warnings ...` to show where the warning was created)
/Users/.../test/main.ts:2
export {};
^^^^^^

SyntaxError: Unexpected token 'export'

Try to fix that by adding the "type": "module" into package.json. Now running pnpm exec ts-node main.ts gives you the very annoying

TypeError: Unknown file extension ".ts" for /Users/.../test/main.ts
    at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:176:9)
    at defaultGetFormat (node:internal/modules/esm/get_format:219:36)
    at defaultLoad (node:internal/modules/esm/load:143:22)
    at async ModuleLoader.load (node:internal/modules/esm/loader:555:7)
    at async ModuleLoader.moduleProvider (node:internal/modules/esm/loader:434:45)
    at async link (node:internal/modules/esm/module_job:87:21) {
  code: 'ERR_UNKNOWN_FILE_EXTENSION'
}

Adding --esm flag does not change anything as the command pnpm exec ts-node --esm main.ts also gives the same error above.

Version used in this test:

• ts-node - 10.9.2
• typescript - 5.8.2
• node - v20.18.0
• pnpm - 9.13.0

[median-dxz]

@timjam I encountered exactly the same problem, and I'm also using Node.js v20. In my case, I have to create a typescript-hooks.mjs file for each of my projects, and run ts file with node --import=./typescript-hooks.mjs

import { register } from 'node:module';
import { setUncaughtExceptionCaptureCallback } from 'node:process';
import { pathToFileURL } from 'node:url';
setUncaughtExceptionCaptureCallback((err) => {
    console.error(err);
});
register('ts-node/esm', pathToFileURL('./'));