[ERROR] Must use import to load ES module

[angelhdzmultimedia]

Issue description

Context

Totally new Node project with typescript, @types/node, and ts-node-dev packages installed.
I only get this error when I set type: "module" in package.json.

ts-node-dev: ^2.0.0

OS version (is it docker or host?), ts-node-dev version

Did you try to run with ts-node?

Did you try to run with --files option enabled?

Did you try to run with --debug option enabled?

Do you have a repro example (git repo) with simple steps to reproduce your problem?

[danlupascu]

I'm having the same problem

ts-node-dev version: 2.0.0
typescript version: 4.7.2

[angelhdzmultimedia]

Switched to babel with @babel/preset-typescript, and nodemon. Everything is working there. Can use imports without filenames, can use directories with implied index.ts, and can use mongoose. Will try other packages later to confirm that everything works now.

[angelhdzmultimedia]

Still having this issue with ts-node-dev. No matter what I try (type: "module" in package.json, module:"esnext" and module:"commonjs" in tsconfig.json, etc.)

Right now, my problem is with the package inquirer. It's ready for ESM in new version v9.0.0. But if I remove type: "module" from package.json, inquirer complains. Then I replaced the import with a dynamic import await import('inquirer'), but then I get an error that can't use top level await with a commonjs module...

It's a paradox.

But with babel and nodemon, and babel typescript presets it works flawlessly.

I'm reaching the conclusion that ts-node-dev isn't ready for ESM so I will continue using babel and nodemon.

[halvors]

I have this exact same problem too, would it be possible to support this?

[dawosch]

Same problem.
I'm using ts-node-dev while i'm developing. And there the error occures.
When i build my project for production with bable it's woking.

[angelhdzmultimedia]

Same problem. I'm using ts-node-dev while i'm developing. And there the error occures. When i build my project for production with bable it's woking.
Yeah, with babel works.

You can try this config, I tested it with most ES2022 features (including Top Level Await) and it works.

{
  "type": "module",
  "name": "test_typescript_esm",
  "version": "1.0.0",
  "description": "",
  "scripts": {
    "dev": "nodemon -I --exec node --experimental-specifier-resolution=node  --loader ts-node/esm ./src/main.ts"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "nodemon": "^2.0.19",
    "ts-node": "^10.9.1",
    "typescript": "^4.7.4"
  },
  "exports": "./dist/index.js",
  "devDependencies": {
    "@babel/core": "^7.18.2",
    "@babel/node": "^7.17.10",
    "@babel/plugin-proposal-decorators": "*",
    "@babel/preset-env": "^7.18.2",
    "@types/node": "^18.6.2"
  }
}

mark

[ChromeGG]

Same problem here. I tried with

ts-node-esm --experimental-specifier-resolution=node --transpile-only ./src/index

and it works BUT it'll not restart automatically if files will change

[angelhdzmultimedia]

Update

Besides it working with Babel, I achieved to make it working with nodemon and ts-node.

Install nodemon and ts-node and of course typescript, set type: "module" in package.json,
and set tsconfig.json to:

{
  "compilerOptions": {
    "esModuleInterop": true,
    "moduleResolution": "Node",
    "module": "ESNext",
    "target": "ESNext"
  }
}

And then: nodemon --exec node --loader ts-node/esm src/main.ts

[zhoutengshen]

I also encountered this problem. These contents may help you

node version : v16.13.2

package.json

{
  "devDependencies": {
    "@types/node": "^18.11.18",
    "nodemon": "^2.0.20",
    "ts-node": "^10.9.1",
    "typescript": "^4.9.4"
  },
  "scripts": {
    "dev": "nodemon --exec ts-node index.ts --project ./tsconfig.json"
  },
  "type": "module"
}

tsconfig.json

{
  "extends": "ts-node/node16/tsconfig.json",
  "ts-node": {
    "transpileOnly": true,
    "files": true,
    // Tell ts-node CLI to install the --loader automatically, explained below
    "esm": true,
    "compilerOptions": {
      "module": "ESNext"
    }
  },
  "compilerOptions": {
    "module": "ESNext",
    "moduleResolution": "Node",
    "lib": [
      "DOM",
      "ES2015"
    ],
    "target": "ES2015"
  }
}

[angelhdzmultimedia]

I also encountered this problem. These contents may help you

node version : v16.13.2

package.json

{
  "devDependencies": {
    "@types/node": "^18.11.18",
    "nodemon": "^2.0.20",
    "ts-node": "^10.9.1",
    "typescript": "^4.9.4"
  },
  "scripts": {
    "dev": "nodemon --exec ts-node index.ts --project ./tsconfig.json"
  },
  "type": "module"
}

tsconfig.json

{
  "extends": "ts-node/node16/tsconfig.json",
  "ts-node": {
    "transpileOnly": true,
    "files": true,
    // Tell ts-node CLI to install the --loader automatically, explained below
    "esm": true,
    "compilerOptions": {
      "module": "ESNext"
    }
  },
  "compilerOptions": {
    "module": "ESNext",
    "moduleResolution": "Node",
    "lib": [
      "DOM",
      "ES2015"
    ],
    "target": "ES2015"
  }
}

Thank you!