Search Terms

• ERR_UNKNOWN_FILE_EXTENSION
• Node.js 18.19.0
• Node.js 18.18.2

Expected Behavior

npx ts-node <script.ts> works on Node.js 18.19.0 just as it does with 18.18.2.

Actual Behavior

Since the upgrade to Node.js 18.19.0, the call fails with ERR_UNKNOWN_FILE_EXTENSION.

All other potentially related parameters remained unchanged (e.g. package-lock.json, ts-config.json, etc.).

We discovered this with GitHub workflow runs that run periodically (with schedule) at short intervals; only difference since things started failing is the Node.js version.

Steps to reproduce the problem

• set up Node.js 18.19.2
• set "type": "module" in package.json
• set "esm": true in tsconfig.json
• create main.ts with something like: console.log('Hello world')
• run npx ts-node main.ts

Minimal reproduction

see https://github.com/mlenkeit/ts-node-repro

there's also a GitHub workflow to run this repo against Node.js 18.19.0 and 18.18.2:
https://github.com/mlenkeit/ts-node-repro/actions/runs/7057725777

Specifications

• ts-node version: v10.9.1
• node version: v18.19.0
• TypeScript version: v5.2.2
• tsconfig.json, if you're using one:

  {
    "extends": "@tsconfig/node18/tsconfig.json",
    "ts-node": {
      "esm": true
    },
    "compilerOptions": {
      "allowSyntheticDefaultImports": true,
      "moduleResolution": "Node",
      "module": "ESNext",
      "noImplicitAny": false,
      "strictNullChecks": true,
      "sourceMap": true,
      "outDir": "./dist",
      "resolveJsonModule": false,
      "types": [
        "node"
      ]
    },
    "exclude": ["node_modules"]
  }
  

• package.json:

  {
    "name": "ts-node-repro",
    "private": true,
    "version": "1.0.0",
    "description": "",
    "main": "index.js",
    "type": "module",
    "dependencies": {
      "@tsconfig/node18": "18.2.2",
      "@types/node": "18.16.1",
      "ts-node": "10.9.1",
      "typescript": "5.2.2"
    }
  }
  

• Operating system and version: macOS Sonoma 14.1.1